SPOT  AND  ARC 
WELDING 

BY 

H.A.HORNOR.B.A. 


FRANKLIN  INSTITUTE  LIBRARY 

PHILADELPHIA 
Class . .($. . ./T./. .    Book. .//. . -Z S^.   Accession 7^.^.3 S 


i- 


SPOT  AND  ARC 
WELDING 

BY 

H.  A.  HORNOR,  B.A. 

VICE-PRES.  I.  E.  S.,  FEL.  A.  I.  E.  E.,  M.  FRANKLIN  INST.  OF  PHIIA.,  AUTHOR  OF 
electricity's  part  in  THE  BUILDING  AND  NAVIGATION  OF  SHIPS, 
AND  MANY  OTHER  TECHNICAL  PAPERS 


PHILADELPHIA  AND  LONDON 
J.  B.  LIPPINCOTT  COMPANY 


COPYRIGHT,   1920,  BT  J.  B.  LIPPINCOTT  COMPANY 


PRINTED  BY  J,  B.  LIPPINCOTT  COMPANY 
EAST  WASHINGTON  SQUARE  PRESS 
PHILADELPHIA,  U.  S.  A. 


To  My  Wife 
MARIE  MORSE  HORNOR 

WITHOUT  WHOSE  AFFECTIONATE  AND  UNTIRING 
AID  THIS  BOOK  WOULD  NOT  HAVE  BEEN  WRITTEN 


7  7  ^^>S' 


PREFACE 


Although  electric  welding  has  been  used  for  many 
years  for  repair  work,  there  exists  to-day  a  hesitancy  in 
applying  it  to  new  construction,  especially  to  the  joining 
of  heavy  steel  parts.  It  is  the  purpose  of  this  book  to 
endeavor  to  dispel  this  apprehension.  The  data  of  tests 
made  in  the  spot  welding  of  heavy  steel  plates  by  the 
Emergency  Fleet  Corporation  is  furnished  in  full  with 
the  expectation  that  in  making  this  information  avail- 
able to  shipbuilders  and  others,  they  will  be  able  to  adopt 
this  process  to  their  own  manufacturing  advantage.  In 
like  manner  the  underlying  question  of  arc-welding  proc- 
esses is  fully  discussed  with  the  intent  of  reassuring 
any  one  who  may  doubt  the  ability  of  these  methods  to 
supersede  the  rivet. 

The  author  wishes  to  acknowledge  the  courtesies  ex- 
tended to  him  both  by  those  who  have  contributed  to  the 
text  and  those  who  have  permitted  the  reprinting  of 
valuable  published  material. 

Minerva,  N.  Y.  H.  A.  HoRNOR. 

March,  1920. 


D 

•igitized  by 

the  Internet 

Archive 

in  2015 

https://archive.org/details/spotarcweldingOOhorn 


CONTENTS 


CHAPTER  PAGE 

I.    Materials   1 

II.    Electric-Welding  Systems   14 

III.  Spot  Welding   24 

IV.  Demonstration  of  Heavy  Spot  Welding   38 

V.    General  Applications  of  Arc  Welding   97 

VI.    Discussions  ON  Arc  Welding   105 

VII.    The  Arc  Welder   134 

VIII.    TiiE  All-Welded  Ship   160 

JX.    Theories  of  Electric  Weldinc:    178 

Appendix  I   218 

Appendix  Ii   220 

Appendix  III   224 

Appendix  IV    231 

Appendix  V   253 

Appendix  VI    276 

Appendix  VII   285 


SPOT  AND  ARC  WELDING 


CHAPTER  I 

Materials 

The  essential  consideration  for  those  who  practice 
the  art  of  electric  welding  is  the  character  of  the  mate- 
rials to  be  joined.  As  a  matter  of  fact,  this  principle  has 
been  the  basis  of  all  successful  engineering  achievement 
and  a  lack  of  it  the  cause  for  many  vital  failures.  The 
wide  range  of  processes  combined  with  ingenious  designs 
permits  the  broad  statement  of  probability  that  all  the 
metals  and  their  alloys  may  in  varying  degrees  be  held 
together  by  electric  methods.  This  provides  a  varied 
and  interesting  fi^ld  for  the  engineer  although,  like  un- 
tilled  ground,  there  will  be  found  many  obstacles  in  the 
way  of  cultivation.  The  success  of  the  harvest  will  be  in 
direct  proportion  to  the  thought  bestowed  upon  the 
actions  of  the  metals  when  under  the  treatment  required 
for  their  jointure. 

It  is  not  proposed  to  consider  here  the  welding  of  the 
soft  metals  such  as  gold,  silver,  copper,  tin,  zinc,  alumi- 
num, etc.  It  is  sufficient  to  affirm  that  in  small  articles 
processes  of  electric  welding  have  been  devised  that  sat- 
isfactorily accomplish  such  joints  as  are  needed  for  spe- 
cial industries.  The  processes  employed  are  fully  de- 
scribed in  many  published  articles/  As  metal  is  added  to 
the  objects  joined  the  method  is  referred  to  as  soldering 
rather  than  welding.  On  the  other  hand,  nickel,  copper, 

' "  Electric  Welding,"  by  D.  T.  Hamilton  and  Erik  Oberg,  1918. 
1  1 


2 


SPOT  AND  ARC  WELDING 


and  aluminum  wires  of  small  diameter  are  joined  by 
means  of  a  condenser  spark,  the  process  being  called  per- 
cussion welding.  Interesting  as  these  apphcations  are, 
only  this  brief  mention  can  be  made  in  order  to  allow  a 
full  opportunity  for  the  discussion  of  the  welding  of 
heavy  steel  pieces. 

Definition. — Doctor  Howe  gives  this  definition  of 
steel  in  its  specific  sense:  "  A  compound  of  iron  possess- 
ing, or  capable  of  possessing,  decided  hardness  simul- 
taneously with  a  valuable  degree  of  toughness  when  hot 
or  when  cold,  or  both.  It  includes  primarily  compounds 
of  iron  combined  with  from,  say,  0.30  to  2  per  cent,  of 
carbon,  which  can  be  rendered  decidedly  soft  and  tough 
or  intensely  hard  by  slow  and  rapid  cooling  respectively, 
and  secondarily,  compounds  of  iron  with  chromium, 
tungsten,  manganese,  titanium,  and  other  elements,  com- 
pounds which  like  carbon  possess  intense  hardness  with 
decided  toughness.^  "  The  reasons  underlying  the  be- 
havior of  this  material  when  subjected  to  temperature 
changes  must  be  sought  for  in  the  researches  made  by 
eminent  metallurgists.  This  is  the  broad  subject  of  the 
heat  treatment  of  steel  with  which  the  practical  welding 
engineer  should  have  some  knowledge  in  order  to  escape 
the  error  of  applying  electric  welding  to  the  detriment 
of  the  original  materials. 

Production  of  Iron. — Iron  ore  when  taken  from  the 
earth  may  contain  many  and  various  minerals.  The  ore 
is  treated  in  a  blast  furnace  for  the  purpose  of  removing 
the  oxygen  which  had  a  persistent  affinity  for  the  pure 
iron.   The  product*  of  the  blast  furnace  is  not  chemically 

'"Metallurgy  of  Steel,"  by  H.  M.  Howe,  vol.  i,  chap,  i,  p.  1,  ^nd 
Ed.,  1891. 


MATERIALS 


3 


pure,  consisting  usually  of  iron,  carbon,  silicon,  manga- 
nese, sulphur,  phosphorus,  and  oxygen.  Pure  iron  may 
be  obtained  by  careful  preparation  in  the  laboratory  but 
not  for  commercial  purposes.  This  molten  metal  from 
the  furnace  is  cast  into  a  form  called  "  pig  iron."  When 
pig  iron  is  remelted  in  a  crucible  and  cast  into  some 
commercial  form  it  is  called    cast  iron." 

Cast  iron  takes  two  forms,  depending  upon  its  treat- 
ment when  poured.  If  the  molten  metal  is  cast  in  sand 
it  is  a  grey  iron  casting,  if  it  is  cast  in  metal  moulds 
(chilled)  it  is  a  white  iron  casting.  The  point  to  observe 
here  is  the  difference  caused  by  the  slow  and  rapid  cooling 
of  the  molten  metal.  The  names  given  to  these  castings 
are  taken  from  the  appearance  of  the  fracture  caused  by 
the  large  amount  of  free  carbon  in  a  case  of  grey  cast 
iron  and  the  small  amount  of  free  carbon  in  the  case  of 
white  cast  iron. 

Annealing  is  effected  by  slow  cooling  from  a  high 
temperature.  If  then  white  iron  castings,  which  are 
brittle  as  compared  to  grey  iron  castings,  are  annealed  so 
as  to  free  the  carbon  which  is  in  a  combined  state,  mal- 
leable castings  will  result.  Malleable  iron  is  free  iron 
with  which  is  mixed  carbon  in  a  free  state  in  the  form  of 
graphite.  The  effect  of  annealing  does  not  penetrate  the 
mass  of  metal  and  annealed  castings  seldom  show  any 
effect  much  further  than  an  inch  below  the  surface. 

When  pig  iron  is  melted  in  a  puddling  furnace  at  a 
point  where  the  pure  iron  appears  to  separate  from  the 
mass  of  impurities  it  is  removed  and  the  slag  that  it 
tenaciously  carries  with  it  is  squeezed  out  by  means  of 
rolls.  The  rolls  naturally  form  the  mass  of  metal  into  the 
shape  of  bars.    This  mechanical  treatment  of  the  iron 


4 


SPOT  AND  ARC  WELDING 


tends  to  produce  purity  and  its  efficiency  is  in  direct  ratio 
to  the  quality  of  the  resultant  wrought  iron.  From  the 
mechanical  treatment  it  receives  it  derives  the  name  of 
wrought  iron.  The  purity  also  bears  a  direct  relation  to 
the  ore,  and  for  this  reason  imported  iron  (Norway  and 
Swedish)  is  well  known  for  this  quality.  Wrought  iron 
because  of  its  purity  is  used  in  the  manufacture  of  high- 
grade  crucible  steel. 

Steel  Processes, — The  essential  difference  between 
the  manufacture  of  steel  by  the  open-hearth  or  crucible 
processes  is  disclosed  by  their  names.  In  the  latter  case, 
iron  of  like  or  unlike  carbon  percentage  is  melted  in 
crucibles  usually  totally  enclosed,  the  molten  mass  is 
held  in  these  crucibles  (either  graphite  or  clay),  so  that 
it  may  absorb  silicon  from  the  crucible  walls,  and  then 
the  liquid  metal  poured  into  castings  or  ingot  forms. 
The  open-hearth  process  melts  the  pig  iron  in  a  cupola, 
transfers  it  to  an  apparatus  whereby  the  impurities  are 
removed  after  which  desired  elements  may  be  added  to 
obtain  various  properties  in  the  finished  steel.  The 
process  is  referred  to  by  steel  makers  as  basic  or  acid  in 
accord  with  the  chemical  nature  of  the  lining  of  the 
vessel  used  for  removing  the  impurities.  Crucible  steel 
is  of  high  grade,  more  expensive  of  manufacture  and 
more  costly.  It  is  used  for  cutting  tools,  springs,  fire- 
arms, etc.  The  added  elements  in  the  open-hearth 
process  may  be  varied  in  many  ways,  thus  producing 
many  steel  alloys  useful  to  the  industries.  For  ordinary 
plates  and  shapes  the  controlling  elements  are  carbon 
and  manganese.  Both  these  elements  hold  high  favor 
due  to  their  ability  to  add  greatly  to  the  tensile  strength 
and  ductility  of  steel. 


MATERIALS 


5 


From  the  steel  furnace  by  either  process  the  metal  is 
cast  either  into  moulds  for  steel  castings  or  ingot  moulds 
for  rolling  into  plates  or  shapes  or  into  billets  for  forg- 
ing. It  should  be  carefully  noted  that  plates,  with  which 
the  electric-welding  engineer  is  much  concerned,  are 
really  steel  castings  which  have  received  additional  tem- 
perature and  mechanical  treatment  in  proceeding 
through  the  rolling  mill.  In  applying  the  processes  of 
spot  and  arc  welding  to  new  steel  construction  it  will  be 
such  material  that  will  require  successful  joining.  As 
heat  is  the  prerequisite  for  the  welding  of  the  metals  in 
any  case  it  becomes  necessary  to  give  close  attention  to 
the  theories  of  the  heat  treatment  of  steel,  the  metallurgy 
of  steel.   This  subject  will  be  taken  up  in  a  later  chapter. 

Chemical  Constituents  of  Steel. — Without  proceed- 
ing into  a  maze  of  theoretical  argument  it  may  be  well  to 
consider  briefly  a  few  opinions  regarding  the  effects  of 
the  various  elements  added  to  steel  and  following  that 
their  composite  action  on  the  weldability  of  steel. 

"  As  the  carbon  increases,  the  tensile  strength,  elastic 
limit,  elastic  ratio,  and  compressive  strength  increase 
within  limits;  the  fusibility,  hardness,  and  hardening 
power  increase  perhaps  without  limit;  while  the  malle- 
ableness  and  ductility,  both  hot  and  cold,  and  the  welding 
power  diminish  apparently  without  limit.  The  modulus 
of  elasticity  appears  nearly  independent  of  the  percent- 
age of  carbon,  at  least  within  the  limits  of  carbon  zero  to 
carbon  two  per  cent."  ^ 

Silicon  is  considered  by  some  authorities  to  cause  brit- 
tleness  and  redshortness,  and  by  others  to  be  in  many 

"  Metallurgy  of  Steel,"  by  H.  M.  Howe,  vol.  i,  chap,  ii,  p.  13,  2nd 
Ed.,  1891. 


6 


SPOT  AND  ARC  WELDING 


cases  harmless,  sometimes  even  increasing  the  ductihty 
and  in  the  presence  of  manganese  "  to  counteract  its 
tendency  to  cause  redshortness."  ^ 

Phosphorus  is  an  undesirable  element.  It  is  well 
known  to  cause  "  coldshort  "  or  brittleness.  The  steel 
manufacturer  takes  every  care  to  remove  as  much  of  this 
element  as  possible  so  that  only  a  small  percentage  is 
found  in  good  commercial  grades  of  steel.  It  is  negligi- 
ble as  far  as  welding  problems  are  concerned. 

The  same  remarks  apply  to  sulphur.  Howe  states: 
"  Sulphur  has  the  specific  effect  of  making  iron  exceed- 
ingly brittle  at  a  red  heat  and  of  destroying  its 
welding  power."  ^ 

The  effect  of  manganese  on  steel  is  still  in  the  regions 
of  dispute.  One  of  the  best  authorities  states:  The  net 
effects  of  manganese  on  tensile  strength  and  ductility 
are  slight."  Manganese  seems  to  promote  continuity 
and  in  this  manner  aids  the  ductility  of  steel.  This  is  an 
important  characteristic  of  this  element  which  may 
throw  light  upon  its  use  in  the  composition  of  electrodes 
for  arc  welding. 

Chromium  gives  hardness  to  hardened  steel  probably 
increasing  the  tensile  strength  and  elastic  limit.  The 
weldability  of  steel  is  reduced  by  chromium. 

The  addition  of  tungsten  tends  to  produce  great 
hardness  in  the  steel  alloy.  This  characteristic  which 
it  retains  at  high  temperature  makes  it  useful  for  the 
manufacture  of  high-speed  cutting  tools.  Tungsten 

''"Metallurgy  of  Steel,"  by  H.  M.  Howe,  vol.  i,  chap,  iii,  p.  40,  9nd 
Ed.,  1891. 

^ "  Metallurgy  of  Steel,"  by  H.  M.  Howe,  vol.  i,  chap,  iii,  p.  52,  2nd 
Ed.,  1891. 


MATERIALS 


7 


steel  is  brittle  and  is  difficult  to  forge  even  at  relatively 
high  temperatures.  Doctor  Howe  doubts  if  it  can  be 
truly  welded  by  ordinary  methods. 

Nickel  steel  surpasses  the  best  carbon  steel  in  its 
superior  tensile  strength  combined  with  elongation. 
Upon  its  first  introduction  it  was  found  difficult  to  ma- 
chine, but  this  disadvantage  has  been  overcome  by  im- 
provements in  machine  tools.  This  alloy  is  also  less 
liable  to  corrosion  than  steel. 

Vanadium  influences  steel  in  much  the  same  manner 
as  nickel.  Its  first  introduction  was  heralded  by  claims 
which  soon  disappeared  in  the  presence  of  tungsten  steel. 

Copper  and  iron  act  curiously  in  combination.  A 
little  copper  with  iron  or  a  little  iron  with  copper  are 
said  to  unite  into  a  homogeneous  mass,  but  if  the  propor- 
tions approach  equality  they  seem  to  split  up  into  alloys. 
The  effect  of  copper  is  like  that  of  sulphur,  causing  red- 
shortness,  brittleness,  and  an  opposition  to  welding.  This 
tendency  of  the  metals  must  be  carefully  held  in  mind 
by  those  who  seek  to  improve  the  non-corrodibility  of  an 
arc-welded  seam  by  the  introduction  of  copper  into  the 
composition  of  the  electrode  material. 

Many  other  metals,  such  as  zinc,  tin,  lead,  titanium, 
arsenic,  cobalt,  aluminum,  may  occur  in  iron  but  disap- 
pear in  the  manufacture  of  steel.  Those  that  have  been 
treated  in  brief  detail  above  are  to  be  found  in  commer- 
cial steel  and  must  be  investigated  by  those  who  are  de- 
sirous of  making  a  successful  application  of  the  practical 
processes  of  electric  welding.  For  those  who  wish  to 
investigate  and  experiment  with  steel  compositions  for 
the  betterment  of  any  special  welding  process  there  re- 
mains the  action  of  the  alkaline  earths  and  the  combina- 


8 


SPOT  AND  ARC  WELDING 


tion  of  iron  with  the  noble  metals.  This  latter  field 
attracted  the  attention  of  some  of  the  older  and  illus- 
trious scientists  without  material  success,  but  the  sign  of 
their  failures  may  by  modern  methods  be  turned  to  a 
mark  of  attainment. 

Weldability  of  Steel. — The  important  consideration 
for  the  welding  engineer  is  the  degree  of  weldability  of 
the  metals  placed  before  him  to  join.  Not  only  is  this 
knowledge  of  great  concern  prior  to  the  performance  of 
the  work,  but  also  is  necessary  for  the  investigation  of 
immediate  and  subsequent  failures.  Commercial  steel 
castings  upon  analysis  show  a  general  chemical  composi- 
tion as  follows : 


Of  these  five  chemical  elements  the  proportion  of 
phosphorus  and  sulphur  are  so  slight  as  to  make  them 
negligible.  Among  technicians  there  is  argument  re- 
garding sulphur.  The  extreme  is  that  0.02  per  cent, 
sulphur  opposes  welding,  the  other  extreme  that  suc- 
cessful welds  can  be  made  with  sulphur  as  high  as  0.07 
per  cent.  Sulphur  as  high  as  0.15  per  cent,  is  consid- 
ered quite  unweldable."  There  remains  the  three  prin- 
cipal constituents,  carbon,  silicon,  and  manganese,  of 
which  many  scholars  give  carbon  the  leading  place  in 
lessening  the  weldability  of  the  alloy.  This  opinion  is 
largely  borne  out  in  practice.  The  whole  subject  resolves 
itself  into  one  needing  at  the  present  time  much 
earnest  study  and  careful  research,  especially  when  con- 


Carbon 

Silicon 


0.35  per  cent. 

0.40  per  cent. 

0.80  per  cent. 

0.05  per  cent. 

0.05  per  cent. 


Manganese 
Phosphorus 
Sulphur    .  . 


MATERIALS 


9 


sidered  with  the  comphcations  introduced  by  the  are- 
welding  process. 

As  regards  manganese  and  sihcon  so  Httle  of  their 
reactions  are  known  that  no  trustworthy  statements  can 
be  made  other  than  those  quoted  and  referred  to  above.  • 
Doctor  Howe  says  of  sihcon:  The  good  welding  power 
of  crucible  steel,  usually  rich  in  silicon,  goes  to  show  that 
silicon  is  not  especially  injurious  in  this  respect."  For 
the  benefit  of  the  practitioner  and  the  art  as  a  whole  it 
would  be  well  for  some  of  our  colleges  to  engage  in  this 
industrially  useful  field  of  research. 

The  carbon  content  has  received  more  careful  and 
substantial  investigation  with  the  result  that  more  har- 
mony of  opinion  exists.  The  same  authority  states:  "  It 
was  formerly  thought  that  the  presence  of  a  little  carbon 
was  indispensable  or  at  least  very  favorable  to  welding; 
but  this,  I  think,  is  no  longer  believed.  Certain  it  is  that 
in  general  the  difficulty  of  welding  increases  with  the 
proportion  of  carbon,  and  the  welding  power  probably 
practically  disappears  when  the  carbon  rises  above  1.3 
per  cent.  The  larger  the  proportion  of  other  elements 
present,  probably  the  lower,  in  general,  is  the  welding 
power  for  given  percentage  of  carbon.  Thus  the  weld- 
ing of  apparently  common  Bessemer  steel  is  said  to  be 
hardly  possible  with  0.20  to  0.35  per  cent,  of  carbon,  and 
impracticable  with  0.35  to  0.50  per  cent.;  while  to  the 
practiced  worker  the  welding  of  the  relatively  pure 
crucible  steel  is  said  to  be  easy  with  0.87  per  cent.,  and 
possible,  using  the  greatest  care,  with  1.25  per  cent,  of 
carbon.    Though  the  difference  is  probably  much  less 

"  Metallurgy  of  Steel,"  by  H.  M.  Howe,  vol.  i,  chap,  xiv,  p.  2nd 
Ed.,  1891. 


10 


SPOT  AND  ARC  WELDING 


than  this  rather  loose  wording  implies,  and  though  there 
are  welds  and  welds,  it  appears  to  be  very  marked. 

"  A  reason  why  rising  carbon  lowers  the  welding 
power  is  that  it  lowers  the  point  to  which  we  can  heat 
the  metal  without  danger  of  burning,  but  does  not  lower 
correspondingly  the  temperature  at  which  plasticity  sets 
in;  indeed,  it  seems  to  diminish  the  plasticity  and  ad- 
hesiveness for  given  temperatures."  ^ 

Doctor  Howe  is  here  treating  purely  of  the  weld- 
ability  of  steel  in  general  and  his  statements,  although  in 
a  large  degi-ee  apply,  must  not  be  construed  as  referring 
to  the  electric  weldability  of  steel.  To  indicate  his  agree- 
ment with  others  and  subjecting  the  question  to  a  spe- 
cific reference  to  electric  welding  the  following  opinion 
is  also  quoted:  "  Little  is  known  at  the  present  time  re- 
garding the  effect  of  the  weldability  produced  by  the 
presence  of  most  of  the  impurities  given  above,  where 
the  electric  arc-welding  process  is  used.  No  data  has 
been  published  on  the  subject.  It  is  known,  however, 
that  steel  containing  0.5  per  cent,  or  more  carbon  is  sub- 
ject to  "  burning  "  at  much  lower  temperatures  than 
low-carbon  steels.  This  fact  can  readily  be  observed  in 
arc-welding  practice,  i.e.,  the  tendency  being  towards 
"  burnt  "  metal  in  the  weld.  The  observations  which 
have  been  made  up  to  the  present  time  seem  to  indicate 
that  the  tendency  toward  "  burning  "  shown  in  steel  of 
comparative  high-carbon  content,  is  the  only  considerable 
effect  which  is  produced  on  the  weldability  by  the  pres- 
ence of  any  of  the  impurities  in  their  usual  amounts." 

Physical  Characteristics. — The  foregoing  opinions 

^  "  Metallurgy  of  Steel,"  by  H.  M.  Howe,  vol.  i,  chap,  xiv,  p.  251,  2nd 
Ed.,  1891. 


MATERIALS 


11 


deal  with  the  chemical  nature  of  steel  and  are  given  con- 
cretely with  the  hope  that  the  practitioner  may  find  them 
convenient  in  his  daily  application  of  electric  welding. 
Of  an  equal  degree  of  importance  are  the  physical 
changes  that  take  place  in  steel  when  subjected  to  high 
and  low  temperature,  sudden  and  slow  changes  of  tem- 
perature. Here  is  to  be  considered  not  the  composition 
nor  the  changes  of  composition  of  the  material,  but 
simply  its  physical  properties. 

Steel  is  hardened  by  rapid  cooling  from  a  high  tem- 
perature. This  is  practically  attained  by  quickly  im- 
mersing the  heated  steel  in  a  bath  of  water  or  oil.  The 
kind  of  liquid  used  to  quench  the  steel  develops  a  greater 
degree  of  tensile  strength  and  different  methods  must  be 
pursued  for  difference  in  carbon  content.  Thus  it  is 
stated  that  to  give  the  highest  tensile  strength  to  low 
carbon  steel  it  should  be  quenched  in  water  from  a  high 
temperature;  for  mild  carbon  steel  (0.40  per  cent.)  it 
should  be  quenched  in  oil  with  a  "  rather  high  quenching 
temperature;  "  ^  and  for  steel  with  large  percentage  of 
carbon  (1.25  per  cent.)  it  should  cool  slowly  from  a  low 
temperature  and  immersed  in  oil.  In  general  the  hard- 
ening of  steel  brings  about  the  desirable  physical  char- 
acteristics of  better  elastic  limit,  greater  firmness,  and 
better  tensile  strength.  The  ductility  tends  to  diminish 
as  well  as  the  specific  gravity.  Steel  may  be  quenched 
in  other  media  such  as  tallow,  coal  tar,  and  even  lead, 
but  tensile  strength  is  not  bettered  by  these  methods  over 
the  use  of  oil. 

The  tempering  of  steel  is  employed  to  modify  to 
some  extent  the  previous  effects  of  hardening.    This  re- 

Metallurgy  of  Steel,"  by  H.  M.  Howe,  vol.  i,  chap,  li,  p.  19,  ^nd 
Ed.,  1891. 


12 


SPOT  AND  ARC  WELDING 


quires  the  reheating  but  to  a  lower  temperature  and  then 
in  general  cooling  quickly  and  in  some  cases  slowly.  As 
hardened  steel  is  brittle  tempering  increases  its  ductility 
and  makes  it  much  tougher.  It  does  this  without  decreas- 
ing the  tensile  strength  and,  in  fact,  it  has  been  stated 
to  increase  the  tensile  strength.  Though  the  ductility  is 
bettered  by  tempering  over  that  of  the  hardening  process 
it  is  still  not  as  ductile  as  annealed  steel.  The  advantage 
of  tempering  which  apparently  is  an  unnecessary  second 
operation  lies  in  the  better  control  of  temperature  with 
the  result  that  hardness  and  tensile  strength  are  not  im- 
paired but  to  them  is  restored  the  ductility  lost  in  the 
hardening  operation. 

The  annealing  of  steel  is  to  completely  undo  the 
effects  of  hardening  and  bring  the  steel  to  a  very  soft 
and  tough  state.  "  It  increases  the  ductility  and  specific 
gravity  and  it  generally  lowers  the  elastic  limits."  ^  Be- 
sides restoring  the  tensile  strength  of  violently  hard- 
ened steel  annealing  also  restores  the  tensile  strength 
caused  by  cold  working  and  internal  stresses  in  steel  cast- 
ings. Much  of  the  advantage  gained  by  annealing  re- 
sides in  the  cooling  temperature  and  the  medium  used 
for  the  cooling  process.  It  may  be  stated  broadly  that 
slow  cooling  brings  about  the  softer  and  tougher  quali- 
ties desired,  but  for  many  purposes  both  cold-worked 
low-carbon  steel  and  steel  castings  the  cooling  may  be 
interrupted  at  a  certain  point  and  the  material  quenched. 
This  procedure  will  not  give  results  equal  to  full  slow 
cooling,  but  often  will  serve  the  purposes  required. 

It  is  thus  seen  that  iron  and  steel  in  many  shapes  and 
with  a  great  variety  of  physical  properties  will  be  laid 

""Metallurgy  of  Steel,"  by  H.  M.  Howe,  vol.  i,  chap,  ii,  p.  24,  2hd 
Ed.,  1891. 


MATERIALS 


13 


before  the  electric- welding  engineer,  and  it  will  depend 
more  or  less  upon  his  familiarity  with  this  wide  range  of 
conditions  how  he  will  meet  and  solve  the  problems.  This 
brief  resume  from  the  mining  of  the  iron  ore  to  its  fabri- 
cation for  use  in  the  mechanic  arts  is  a  necessary  prelimi- 
nary to  the  study  and  practice  of  the  joining  of  steel  by 
electric  power.  To  materials  that  have  already  been 
subjected  to  modifications  in  their  chemical  constituents, 
to  changes  in  their  physical  properties  by  the  application 
of  different  temperatures,  and  to  internal  mutations  of 
their  own  making — to  these  materials  are  applied  chemi- 
cal reactions,  and  physicaLeff  ects  of  like  nature  to  obtain 
a  connection  which  will  either  approach  or  exceed  the 
advantageous  characteristics  of  the  original  metal.  It 
is  mainly  upon  this  point  that  objectors  to  electric  weld- 
ing rest  their  argument :  that  no  joint  can  be  equal  to  the 
original  material.  It  is  upon  the  same  point  that  those 
who  are  favorable  toward  and  well  acquainted  with  elec- 
tric welding  uphold  their  belief  in  the  process  because 
the  e^ddence  has  accumulated  to  a  degree  which  permits 
the  statement:  that  electric- welded  joints  can  be  made 
which  will  be  stronger  than  the  metals  joined. 

Summary. — This  plainly  places  before  the  engineer 
a  new  problem,  namely,  whether  he  wishes  his  jointures 
to  be  more  or  less  lasting  than  the  materials  which  he  is 
using  for  a  given  purpose.  On  the  other  hand,  with  this 
new  ability  to  secure  a  more  favorable  joint  will  he  not 
economically  and  safely  reduce  the  amount  of  materials 
to  secure  the  same  result?  These  engineering  problems 
are  closely  knit  with  a  study  of  the  metallurgy  of  steel 
and  the  modern  applications  of  electricity  to  the  weld- 
ing of  steel. 


CHAPTER  II 


Electric- WELDING  Systems 


Fundamental  principles  separate  electric-welding 
processes  into  two  distinct  groups:  resistance  methods 
and  arc  methods.  As  its  name  implies,  resistance  weld- 
ing is  accomplished  by  the  phenomenon  of  the  transfor- 
mation of  electric  energy  into  heat  energy  by  opposition 
to  the  flow  of  current.  The  arc  method  follows  the  be- 
havior of  the  electric  circuit  whenever  it  is  suddenly 
opened,  namely,  the  production  of  a  spark  which  if  the 
distance  between  the  terminals  is  maintained  will  pre- 
serve an  arc.  It  was  this  characteristic  of  electricity  that 
produced  the  first  electric-lighting  unit,  the  arc  lamp; 
and  the  former,  or  resistance  characteristic,  that  fur- 
nished the  incandescent  lamp. 

Many  processes  of  welding  have  been  devised  from 
these  two  primary  groups  but,  as  will  be  seen,  the  dif- 
ferences rest  entirely  on  details  generally  associated  with 
special  applications.  The  following  diagram  gives  the 
sub-divisions  of  each  group : 


Resistance  Processes 


Arc  Processes 


1.  Butt  welding 

2.  Spot  welding 

3.  Seam  welding 


1.  Carbon  arc  welding 

2.  Metallic  arc  welding 


a.  Bare  electrode 
6.  Covered  electrode 

1.  Gas  flux 

2.  Liquid  flux 


Butt  Welding. — This  process  consists  of  bringing 
two  pieces  of  metal  into  contact  end  on  end  and  then 

14 


ELECTRIC-WELDING  SYSTEMS  15 


clamping  these  ends  between  two  jaws  of  high  conduc- 
tive material  supphed  with  high  current  at  low  voltage 
from  the  secondary  of  a  transformer.  With  pressure 
applied  forcing  the  two  pieces  together  and  the  current 
turned  on,  a  localized  welding  temperature  is  provided 
which,  as  the  operation  is  visible  at  all  times,  may  be  held 
on  until  proper  fusion  results.  It  is  usual  practice  to 
maintain  the  pressure  for  a  short  time  after  the  current 
is  turned  off.  Due  to  the  end  pressure  a  burr  will  form 
at  the  juncture  of  the  pieces  aiding  the  observer  to  make 
a  satisfactory  weld.  As  the  outer  surface  of  the  metals 
tends  to  conduct  heat  away  from  the  point  of  contact  of 
the  clamping  jaws  so  advantageously,  the  interior  metal 
offering  the  greater  resistance  will  arrive  at  a  welding 
heat  before  the  exterior.  This  feature  protects  the  proc- 
ess from  any  doubt  as  to  the  soundness  of  the  finished 
weld.  In  blacksmith  welding  the  reverse  is  true  and  the 
finished  weld  exteriorly  may  look  sound  but  in  reality 
cover  poor  fusion.  There  is  a  large  field  in  the  industries 
for  the  application  of  butt  welding,  especially  for  the 
welding  of  tool  shanks,  rods,  etc. 

Spot  Welding. — This  process  is  so  called  because 
the  materials  are  not  joined  together  continuously,  but 
spaced  as  in  riveting.  Plates  are  lapped  and  then 
brought  to  a  machine  and  placed  as  in  butt  welding  be- 
tween two  high  conducting  points.  Spot  welding  for 
this  reason  is  frequently  referred  to  as  "  point  "  welding. 
Pressure  is  brought  to  bear  upon  these  points,  current  of 
high  value  is  turned  on,  the  materials  at  the  points  are 
thus  raised  to  a  welding  temperature,  current  is  then 
removed,  the  pressure  released,  and  the  weld  completed. 
The  intensity  of  the  current  produces  a  very  rapid  rise 


16 


SPOT  AND  ARC  WELDING 


of  temperature  which  with  the  pressure  tend  to  prevent 
the  ill  effects  of  entrapping  oxygen  in  the  weld.  This 
characteristic  assists  in  practice  to  blow  out  the  slag 
which  may  form  on  the  surfaces  of  the  plates.  It  is 
natural  to  see  an  analogy  between  smith  welding  and 
resistance  welding,  for  just  as  the  smith  heats  his  mate- 
rials in  a  forge  and  then  applies  pressure  with  his  ham- 
mer, so  the  spot-welding  machine  raises  the  material  to 
welding  heat  and  then  applies  pressure.  It  would  be 
reasonable  to  believe  that  the  differences  in  the  applica- 
tion of  pressure  would  have  a  marked  effect  upon  the 
results  in  a  relative  degree  to  the  time  difference  in  the 
raising  of  the  temperature,  but  this  particular  interest- 
ing side  of  spot  welding  has  never  been  fully  investigated 
or  at  least  reported.  Spot  welding  of  light  materials, 
steel  up  to  inch,  has  had  a  remarkable  development  in 
this  country  for  some  years.  Heavy  spot  welding,  steel 
up  to  1  inch,  was  experimented  with  in  the  last  few  years. 
In  the  manufacture  of  automobile  bodies,  metal  furni- 
ture, and  bicycle  parts,  it  has  established  itself  firmly. 
It  is  especially  fitted  for  shop  work,  and  for  new  con- 
struction, but  has  not  been  developed  nor  used  for  repair 
work.  The  decided  advantages  of  resistance  welding 
over  arc  welding  rest  upon  the  fact  that  a  weld  can  be 
made  independently  of  the  operator,  that  the  work  can 
be  done  rapidly  and  in  the  open,  and  that  it  permits  of 
practical  inspection.  As  will  be  seen  later  these  points 
of  advantage  give  a  confidence  in  results  not  accorded  to 
any  of  the  practical  processes  of  arc  welding.  It  is  for 
this  reason  that  those  who  are  responsible  for  new  con- 
struction work  are  less  conservative  to  the  introduction 
of  spot  welding  on  a  large  scale. 


ELECTRIC-WELDING  SYSTEMS  17 


Seam  Welding. — A  minor  application  of  resistance 
welding  is  employed  on  very  thin  sheets  for  making  a 
continuous  seam.  Instead  of  clamping  jaws,  or  points, 
the  current  is  led  to  the  work  on  rollers  under  pressure. 
It  is  possible  that  this  method  may  be  capable  of  exten- 
sion to  heavier  materials  but  it  has  not  been  shown  by 
any  large  commercial  use.  The  seam  welded  success- 
fully in  this  way  would  undoubtedly  provide  a  ready 
means  for  obtaining  fluid-tight  work  and  its  point  of 
economy  would  then  rest  upon  the  speed  with  which 
good  welding  could  be  accomplished.  When  consider- 
ing fluid-tight  work  one  point  of  vital  difference  must  be 
borne  in  mind,  namely,  the  simple  retaining  of  the  liquid 
in  the  vessel  as  against  the  hquid  under  pressure.^  It 
may  be  stated  as  a  general  precaution  that  all  electric- 
welding  processes  should  be  carefully  investigated  be- 
fore applying  them  to  work  involving  danger  to  human 
life.  Doubtless  future  research  will  permit  this  work  to 
be  done,  but  the  applications  not  involving  such  risks 
are  plentiful. 

Carbon  Arc  Welding. — In  this  process  an  arc  is  held 
between  the  metals  to  be  joined  and  a  pencil  or  rod  of 
carbon.  In  all  arc  welding  the  rod  used  for  maintaining 
the  arc  and  manipulated  by  the  operator  is  called  the 
electrode.  The  carbon  electrode  is  connected  to  the 
negative  side  of  a  low  potential  circuit  (60  to  75  volts) 
and  the  work  to  the  positive  side.  A  very  intense  heat  is 
produced  by  the  carbon  arc  which  draws  from  the  elec- 
tric supply  300  to  600  amperes.  Flanged  or  butted 
edges  of  thin  tank  steel  (1/16  inch  and  3/32  inch  thick) 
are  satisfactorily  fused  together  by  the  carbon  electrode 

^  This  refers  also  to  gases  under  pressure. 

2 


18 


SPOT  AND  ARC  WELDING 


without  added  metal,^  but  steel  of  greater  thickness  re- 
quires a  melt  rod  of  proper  composition  to  supply  the 
filling.  The  process  under  these  conditions  bears  a  simi- 
larity to  soldering.  Where  there  is  a  great  quantity  of 
shop  repetition  work  with  thin  materials,  automatic  ma- 
chines equipped  with  carbon  electrodes  are  feasible  and 
economical.  The  process  is  specially  valuable  in  the 
heating  of  large  areas  and  the  filling  of  large  holes.  It 
is  a  good  tool  for  heavy  repair  work.  It  is  also  possible 
to  cut  metals  with  the  carbon  arc,  but  few  operators  are 
able  to  follow  a  sharp  line  and  thus  the  uncontrolled  arc 
leaves  a  very  poor  working  edge.  It  is  stated  that  the 
carbon  arc  is  economical  for  the  rough  cutting  of  scrap 
materials  and  the  demohtion  of  steel  buildings.  Un- 
doubtedly there  is  a  future  for  this  process  not  only  in 
special  lines,  but  for  extensive  application  to  new  con- 
struction when  methods  have  been  devised  for  the  better 
control  of  the  arc  and  ease  in  manipulation. 

Metallic  Arc  Welding. — By  far  the  greater  propor- 
tion of  electric  welding  is  performed  to-day  with  the 
metallic  electrode.  The  arc  is  held  in  the  same  manner 
and  by  the  same  means  as  in  carbon  welding,  but  the 
connections  are  usually  reversed  as  the  metallic  elec- 
trode supplies  the  filler  for  the  weld  and  a  larger  per- 
centage of  the  thermal  energy  is  conducted  to  the  metals 
being  joined.  The  process  is  far  more  comfortable  for 
the  operator  as  the  heat  is  less  intense  and  more  local- 
ized. It  is  a  cold  process.  One  hand  is  free  in  which  to 
hold  a  screen  for  eye  and  face  protection.  A  low  voltage 
is  required  as  in  the  carbon  process  but  the  current  is 

^  "  Electric  Arc  Welding  in  Tank  Construction,"  R.  E.  Wagner,  General 
Electric  Review,  December,  1918. 


ELECTRIC-WELDING  SYSTEMS 


19 


much  reduced  (50  to  175  amperes) .  The  process  is  very 
simple.  It  makes  a  very  handy  tool  for  any  shop  en- 
gaged in  metal  work  either  for  repairs  or  new  construc- 
tion. The  apparatus  for  metallic  arc  welding  has  its 
reason  in  the  field  of  commercial  economics  and  as  an 
aid  to  the  operator.  An  experienced  operator  should 
be  able  to  make  as  good  a  weld  with  an  electric  circuit 
controlled  through  a  water  resistance  as  with  the  most 
expensive  apparatus  obtainable.  This  is  not  intended  to 
discredit  the  work  done  in  providing  tools  for  the  ad- 
vancement of  arc  welding,  but  it  is  stated  to  protect 
those  who  may  interest  themselves  in  the  practical  appli- 
cations of  this  process  from  the  assertion  that  the  appa- 
ratus irrespective  of  the  operator  will  produce  good  and 
satisfactory  work.  This  process  of  welding  has  had  ex- 
tensive use  in  the  railway  rep  air- shops  in  this  country 
for  many  years,  and  its  expansion  in  this  line  is  evidence 
of  both  its  reliability  for  serious  repairs  as  well  as  its 
economic  value.  In  like  manner  it  has  been  used  for 
repairs  to  marine  boilers  and  other  applications  which 
will  be  considered  later.  The  process  has  not  been  ex- 
tensively employed  on  new  construction  work,  but  its 
adherents  have  recently  given  it  great  impetus  in  this 
direction  in  connection  with  the  hastening  of  the  ship- 
building program  during  the  war.  This  application  re- 
quired not  only  its  extension  to  heavy  materials,  but 
also  its  investigation  by  specialists  to  convince  conserva- 
tive engineers  of  the  shipbuilding  industry. 

Bare  and  Covered  Electrodes, — Arc  welding  has  its 
modifications  like  any  other  process.  Those  who  strive 
to  securely  advance  a  beneficial  art  are  certain  to  fall 
upon  some  weakness  which  may  be  improved  or,  for  spe- 


20 


SPOT  AND  ARC  WELDING 


cial  requirements,  some  strong  point  which  may  be  in- 
tensified. Students  of  the  metaUic-arc  method  while 
watching  the  successes  and  failures  under  varying  con- 
ditions hit  upon  the  theory  that  the  bare  metal  electrode 
brought  oxygen  from  the  air  and  carried  it  into  the  weld. 
Practical  tests  showed  that  the  bare  metal  electrode  pro- 
duced a  brittle  weld,  strong  as  far  as  tensile  strength 
was  concerned,  but  lacking  in  ductility  and  resistance  to 
shock.  Invention  soon  provided  a  cover  for  the  electrode 
and  this  practice  has  become  general  in  England.  In 
this  country  the  practice  has  been  entirely  with  the  bare 
electrode ;  apparatus  has  been  developed  solely  on  these 
lines  and  opinion  is  biased  for  that  reason. 

In  England  two  methods  are  employed,  one  the  use 
of  a  non-conducting  fireproof  sleeve  which  leads  the 
molten  metal  from  the  end  of  the  electrode  and  protects 
it  from  contact  with  the  surrounding  -  air.  The  other 
method  consists  of  an  asbestos  yarn  impregnated  with 
fluxing  compound  wound  upon  the  metallic  electrode. 
This  sleeve  melts  with  the  arc  and  furnishes  a  slag  which, 
while  it  prevents  the  access  of  oxygen  to  the  weld,  must 
also  be  brought  by  the  welding  operator  to  the  surface 
of  the  weld.  If  additional  layers  of  metal  are  necessary 
to  finish  the  joint  the  slag  formed  on  each  layer  must  be 
carefully  chipped  off  before  depositing  the  succeeding 
one.  Many  variations  are  permitted  with  this  system  as 
combinations  may  be  made  with  different  chemical  con- 
stituents in  the  electrode  as  well  as  in  the  flux  covering. 
The  differences  of  opinion  existing  as  they  do  between 
the  two  countries  (America  and  England)  naturally 
creates  an  interesting  discussion  among  welding  engi- 
neers.   It  is  not  proposed  here  to  enter  into  this  dis- 


ELECTRIC-WELDING  SYSTEMS  21 


puted  field.  Certain  engineers  in  this  country  claim  to 
have  produced  welds  with  bare  electrodes  superior  to  or 
equal  in  ductility  to  covered  electrode  welds.  In  Eng- 
land they  are  apparently  unable  to  approach  with  the 
bare  metal  electrode  any  of  the  work  done  by  the  cov- 
ered electrode  process.  Attracted  by  the  claims  of  the 
advocates  of  covered  electrodes  many  American  engi- 
neers are  experimenting  with  coated  electrodes,  i.e., 
simply  immersing  the  metal  electrode  in  a  solution  and 
permitting  it  to  dry  before  using.  In  this  regard  it  is 
well  known  that  a  solution  of  ordinary  whitewash  will 
often  improve  the  welding  quality  of  an  otherwise  poor 
welding  electrode.  This  experimental  attitude  of  the 
American  engineer  at  least  leads  to  the  belief  that  the 
use  of  a  covering  on  the  metal  electrode  is  of  some  advan- 
tage despite  its  cost. 

Other  Processes. — There  are  two  processes  of  electric 
welding  which  will  receive  only  brief  mention  because 
they  have  been  developed  for  special  purposes  and  were 
not  found  applicable  for  the  joining  of  heavy  steel  parts 
such  as  are  usual  in  steel  ship  construction.  They  are 
called  the  electric  blow-pipe  method  and  the  "  water-pail 
forge."  The  latter  is  not  strictly  a  welding  process  in 
that  electricity  is  used  merely  to  heat  the  metal  which  is 
afterwards  forged  in  the  customary  manner.  As  its 
name  implies  one  side  of  an  electric  circuit  is  connected 
to  a  solution  held  in  a  wooden  pail  and  the  other  side  of 
the  circuit  is  connected  to  the  metal  to  be  heated.  In  the 
former  process  the  electric  blow-pipe  is  essentially  a  hori- 
zontal-flame arc  lamp  using  two  carbons  mounted  like 
the  letter  V.  Between  these  two  carbons  is  placed  a 
powerful  magnet  which  creates  a  sufficient  magnetic  field 


22 


SPOT  AND  ARC  WELDING 


to  blow  the  arc  in  the  direction  desired.  This  method  ehm- 
inates  the  passage  of  the  electric  current  through  the 
work  and  is  said  to  be  successful  in  the  welding  of  small 
pieces  of  steel  and  brass.  The  voltex  process  is  a  modi- 
fication of  the  blow-pipe  method  in  which  the  carbon 
electrodes  are  impregnated  with  metallic  oxide  which  is 
vaporized  in  the  flame  of  the  arc.^ 

Besides  these  processes  there  are  many  modifications 
of  details  and  apparatus  connected  with  arc  welding. 
The  simplicity  of  the  electric  circuit  for  arc  welding  has 
already  been  mentioned,  and  it  will  be  seen  later  how 
apparatus  Jias  been  devised  to  aid  the  operator  and  de- 
crease the  cost  of  operation.  Arc  welding  may  be  per- 
formed with  either  direct  or  alternating  current.  The 
advantage  advanced  for  using  the  latter  is  the  simpHcity 
and  inexpensiveness  of  the  apparatus. 

Variations  in  the  chemical  composition  of  the  elec- 
trode material  and  variations  in  current  for  the  welding 
of  different  thicknesses  and  compositions  of  steel  go  to 
make  up  a  catalogue  of  modifications  which  give  great 
latitude  to  the  designer  of  welding  apparatus.  The  use 
of  arc  welding  in  the  shop  for  repetition  work  allows 
ingenuity  of  arrangement  and  connection  of  apparatus. 
For  instance,  several  single  arc-welding  units  may  be 
connected  in  series  if  the  work  will  permit  their  simul- 
taneous use  instead  of  each  unit  being  separately  con- 
nected as  for  general  field  work.  These  are  a  very  few 
of  the  many  possible  modifications  which  the  process  of 
arc  welding  encourages. 

Summary. — From  these  different  methods  the  spe- 
cialist called  to  advise  the  government  upon  the  applica- 

^ "  Electric  Welding,"  Hamilton  and  Oberg,  p.  5,  1918. 


ELECTRIC-WELDING  SYSTEMS 


23 


tion  of  electric  welding  to  ship  construction  selected  spot 
welding  and  metallic  arc  welding  because  they  were 
recognized  for  the  joining  of  light  materials  and  logi- 
cally could  be  quickly  advanced  to  the  state  of  joining 
heavy  steel  plates  and  shapes.  They  proved  that  elec- 
tric-welding processes,  particularly  spot  and  metallic 
arc,  could  be  utilized  for  the  joining  of  steel  plates  of 
inch  in  thickness.  Further,  that  spot  welding  could  be 
employed  for  the  joining  of  greater  thicknesses  and 
also  a  number  of  heavy  pieces.  This  cleared  the  way 
for  the  practical  applications  of  electric  welding  to 
ship  construction. 


CHAPTER  III 


Spot  Welding 

There  are  four  important  points  to  be  considered  in 
either  light  or  heavy  spot  welding :  ( 1 )  The  electric  cur- 
rent requisite  for  producing  the  welding  temperature; 
( 2 )  the  time  in  which  this  current  is  utilized  for  making 
the  weld;  (3)  the  mechanical  pressure  necessary  for  the 
electrical  contact  as  well  as  for  squeezing  the  materials 
during  the  application  of  heat ;  ( 4 )  the  condition  of  both 
surfaces  of  the  two  pieces  of  material  that  are  to  be 
joined.  In  the  spot  welding  of  thin  (or  light)  sheet 
steel  apparently  the  wearing  away  of  the  electrode  points 
is  not  of  prime  importance,  but  in  heavy  spot  welding 
this  feature  becomes  a  serious  matter  when  viewed  from 
a  shop-production  standpoint.  This  point  of  difference 
as  well  as  others  will  be  set  forth  when  the  results  of  the 
demonstration  of  heavy  spot  welding  are  discussed.  In 
general  a  heavier  current  must  be  employed  for  the  weld- 
ing of  greater  thicknesses  of  steel  plates,  more  time  must 
be  consumed,  the  pressure  must  be  increased,  although 
to  what  degree  is  questionable,  and  the  contact  surfaces, 
i.e.,  those  next  to  the  electrode  as  well  as  those  imping- 
ing upon  each  other,  must  receive  the  attention  of  the 
engineer  responsible  for  the  results. 

Apparatus  for  Light  Spot  Welding. — For  this  class 
of  work  the  design  of  machine  may  take  various  forms 
in  conformity  with  the  special  nature  of  the  product. 
For  the  process  alternating  electric  current  is  employed 
because  a  high  current  at  a  low  voltage  is  needed  to 


SPOT  WELDING 


25 


produce  the  welding  heat.  The  usual  voltage  supplied 
to  shops  in  this  country  for  power  purposes  is  220,  and 
this  requires  a  transformer  usually  integral  with  the 
machine.  In  smaller-sized  machines  the  pressin^e  may 
be  secured  by  levers  operated  by  hand  or  foot;  in  larger 
machines  the  practice  is  to  employ  either  water  or  air 


Fig.  1. — Small  spot- welding  machine. 


pressure.  In  like  manner  small  apparatus  may  require 
no  water-cooling  arrangement  for  the  copper  electrodes, 
but  in  larger  machines  this  is  essential.  The  lighter  ma- 
chines may  also  permit  of  the  offsetting  of  the  electrode 
for  performing  in  close  quarters  or  accomplishing  some 
special  object,  but  in  the  heavier  designs  the  pressure 
must  come  directly  in  line  with  the  electrodes.  As  will  be 
seen  in  Fig.  1,  the  secondary  of  the  transformer, 


SPOT  AND  ARC  WELDING 


Fig.  2. — 25-kw.  light  spot-welding  machine. 


which  in  this  case  is  composed  of  thin  copper  strips, 
conducts  the  induced  current  from  the  transformer  to 
the  electrodes.   This  machine  is  used  for  plate  work  and 


SPOT  WELDING 


27 


is  designed  with  the  necessary  gap.  The  electrical  con- 
nections are  arranged  so  that  adjustments  for  current 
may  be  made  for  varying  conditions  of  work.  Auto- 
matic features  may  be  included  in  the  design,  so  that 
repetition  work  can  be  done  with  great  rapidity  and 
with  uniform  results.  Fig.  2  illustrates  another  type  of 
spot- welding  machine  having  a  capacity  of  25  to  30  kw. 
and  capable  of  doing  fairly  heavy  spot  welding.  This 
machine  has  a  small  gap  and  could  not  be  used  for  ex- 
tending over  wide  plates.  It  is  to  be  noted  that  the  pres- 
sure operates  in  a  direct  line  through  the  electrodes. 

Applications  of  Light  Spot  Welding. — As  the  pres- 
sure required  for  light  sheet  steel  (say  1/16  inch  thick) 
is  approximately  very  low,  about  200  to  300  pounds,  the 
application  of  this  method  to  the  fabrication  of  small 
articles  is  very  large.  As  noted,  the  electrodes  may  be 
placed  in  various  positions  and  offset  in  the  electrode 
holder  in  any  manner  required  by  the  special  job.  Thus 
kitchen  utensils,  like  coffee  pots,  saucepans,  etc.,  are 
made  by  spot  welding  the  spout  on  to  the  body,  thus 
facilitating  the  finishing  operation  by  leaving  a  smooth 
surface.  House  fittings,  such  as  doorknobs,  sash  pul- 
leys, etc.,  are  made  by  the  thousand  in  a  very  short  time. 
Small  chains  for  various  purposes  are  made  on  special 
and  very  interesting  machines,  and  the  use  of  this  process 
in  the  bicycle  and  automobile  industries  has  been  respon- 
sible for  decreased  cost.  Many  special  applications  are 
of  interest,  such  as  the  welding  of  the  two  magnet  bars 
in  a  telephone  receiver.  The  difficulty  of  doing  this  by 
other  methods  of  welding  is  that  the  temper  of  the  mag- 
net steel  would  be  drawn  and  so  destroy  the  purpose  for 
which  it  was  intended.^ 


^    Electric  Welding,"  Hamilton  and  Oberg,  p.  121, 


28 


SPOT  AND  ARC  WELDING 


Possibilities  of  Light  Spot  Welding. — Many  opera- 
tions not  strictly  spot  welding  may  be  performed  on  a 
light  spot-welding  machine  (see  Fig.  3) .  By  preparing 
the  materials  in  a  special  way,  by  the  use  of  a  button 
placed  on  the  materials,  by  means  of  special  electrode, 
many  small  articles  can  be  easily  and  quickly  welded. 
Sheets  may  be  welded  to  studs,  bolt  heads  to  body  in  a 
spot-welding  machine,  although  the  operation  bears  a. 
strong  likeness  to  butt  welding.    In  the  same  manner 


Fig.  3. — Special  jobs  done  by  light  spot-welding  machine.   Thick  piece  to  thin  piece.    Many  pieces 

of  thin  sheets  welded  together. 

screws  may  be  welded  to  sheet  tubing.  The  spot-welding 
machine  may  be  utilized  to  heat  rivets  in  place  and 
squeeze  them  "  home,"  thus  performing  as  an  automatic 
riveting  machine.  A  wrongly  pvmched  hole  may  be  cor- 
rected by  introducing  a  proper-sized  stud  and  then  spot 
welding  it  in  place.  This  also  may  be  done  with  heavy 
spot- welding  machines.^  By  arranging  the  edge  of  thin 
sheets  with  projections  which  act  to  localize  the  heat,  and 
with  special  electrodes  or  multiple  electrodes,  a  number 

^ "  Spot  Welding  and  Some  of  Its  Applications  to  Ship  Construction,-' 
H.  A.  Winne,  General  Electric  Review,  December,  1918. 


SPOT  WELDING 


29 


of  spot  welds  may  be  made  in  one  operation.  It  is  stated 
that  there  are  machines  made  with  a  sohd  electrode  of 
copper  against  which  a  single  electrode  is  made  to  move 
at  designed  intervals.  This  apparatus  is  capable  of  mak- 
ing thousands  of  spots  a  minute  and  connecting  thin 
sheets.  It  only  requires  a  fraction  of  time  to  make  a  spot 
in  such  materials."  It  is  not  believed  that  all  the  possi- 
bilities for  light  spot  welding  are  by  any  means  exhausted 
and  undoubtedly  the  introduction  of  heavy  spot  welding 
will  result  in  the  further  extension  of  spot  welding 
in  general. 

Possibilities  of  Spot  Welding  in  Ship  Construction. 
— Although  spot  welding  was  applied  in  the  industries 
only  for  steel  plates  not  exceeding  ^  inch  in  thickness, 
the  results  had  led  many  engineers  to  a  belief  in  its  ex- 
tension to  greater  thicknesses.  So  in  1911  the  American 
Car  &  Foundry  Company  built  a  portable  spot-welding 
machine  with  a  gap  of  66  inches,  so  as  to  €xtend  across 
wide  plates  and  with  which  they  constructed  a  gondola 
freight  car.  The  welding  machine  was  equipped  with 
a  transformer  of  85-kw.  capacity  "  having  a  primary 
voltage  of  400  and  a  secondary  open-circuit  voltage  of 
25.  .  .  .  Pressure  was  applied  by  means  of  a  hand 
wheel,  but  subsequent  machines  were  equipped  with  air 
cylinders  for  applying  the  pressure.  Copper  electrodes 
3  inches  in  diameter  were  used  at  jaw,  the  welding  points 
having  a  diameter  of  }i  of  an  inch.  It  was  found  that 
perfect  welds  could  be  made  with  this  machine  through 
3  sheets  each  ^  inch  thick,  or  2^  inches  total  thick- 
ness." ^   The  results  of  the  completed  car  were  satisfac- 

^ Electric  Welding,"  Hamilton  and  Oberg,  p.  108. 

^  "  An  Electrically-Welded  Freight  Car,"  J.  A.  Osborne,  General  Electric 
Review,  December,  1918. 


30 


SPOT  AND  ARC  WELDING 


tory  in  every  way  and  reports  while  in  service  show  that 
no  abuse  has  occasioned  serious  embarrassment  to  the 
spot-welding  process.  The  engineer  of  this  work  states 
his  opinion:  "  I  believe  that  this  severe  test  of  the  process 
has  demonstrated  the  fact  that  spot  welding  for  heavy 
structures  is  absolutely  practical  and  reliable.  It  has 
demonstrated  that  riveting  can  be  replaced  in  almost  all 
instances.  The  ease  of  manipulation,  as  well  as  the 
great  saving,  will  no  doubt  cause  this  process  to  be 
universally  adopted."  ^ 

For  this  particular  application  a  portable  welding 
machine  of  large  dimensions  was  necessary,  and  the 
makers  of  spot- welding  apparatus  were  evidently  not 
inclined  to  develop  such.  They  had  built  stationary 
machines  of  100-kw.  capacity  and  pressure  of  50  tons 
on  the  electrodes,  but  had  not  considered  designs  of  this 
size  for  portable  use.  The  upper  electrode  of  the  100-kw. 
machine  was  2^/^  inches  in  diameter  and  the  lower  3 
inches  in  diameter,  the  pressure  coming  directly  on  them. 
This  apparatus  was  capable  of  welding  "  two  strips  1^ 
inches  thick."  ^ 

A  long  series  of  tests  were  undertaken  in  1917  at  the 
plant  of  the  New  York  Shipbuilding  Corporation  at 
Camden,  N.  J.  These  tests  were  never  published  in 
detail,  although  an  account  of  them  is  available.  For 
certain  small  operations  a  25-kw.  spot-welding  machine 
was  purchased  in  1916.  This  apparatus  was  the  only 
means  for  carrying  on  the  investigations,  and  therefore 
the  tests  could  not  be  extended  beyond  the  welding  of 
two  thicknesses  of  ^-inch  steel  plate.    The  results  all 

^  Idem. 

^  "  Electric  Welding,"  Hamilton  and  Oberg,  p.  118. 


SPOT  WELDING 


31 


assured  the  use  of  the  process  in  the  fabricating  shops 
with  machines  of  proper  size  and  design.  There  are 
many  pieces  of  the  ship's  structure,  such  as  deck  houses, 
doors,  skyhghts,  hatch  frames,  masts,  stacks,  etc.,  which 
are  put  together  and  form  quite  a  separate  part  from  the 
hull  of  the  ship.  These  various  sub-structures  go  to 
make  up  a  long  list  of  what  is  generally  called  ship's 
fittings.  Such  fittings  rarely  demand  thick  sections,  as 
they  are  not  required  to  resist  heavy  strains  nor  undergo 
excessive  stresses.  Even  in  the  heavier  class  of  vessels 
such  fittings  will  be  made  of  ^-inch  steel,  in  some 
cases  less. 

In  view  of  this  wide  variety  of  work  that  could  be 
done  by  spot  welding  and  the  large  saving  to  be  secured 
by  its  use  led  those  who  were  making  this  investigation 
to  extend  their  trials  to  the  building  of  a  water-tight 
bulkhead  door.  Fig.  4  shows  the  spot  welding  of  the 
3-in.  X  3-in.  X  5/16-in.  angle  frame  to  the  door  plate. 
In  the  endeavor  to  secure  water-tightness  with  a  great 
number  of  spots  and  the  use  of  flux  about  141  spots  were 
made.  It  was  noted  that  a  smaller  number  of  spots  and 
the  edges  of  the  angle  arc  welded  would  give  more  satis- 
factory results.  After  the  door  was  completed  it  was 
placed  with  the  edges  of  the  angle  upon  a  steel  plate, 
securely  clamped  and  made  water-tight  by  the  customary 
methods  used  on  shipboard.  A  water  connection  was 
then  made  and  pressure  gradually  applied.  A  slight  de- 
flection in  the  plate  at  the  top  and  middle  of  the  door  was 
noticeable  when  the  pressure  reached  ten  pounds  per 
square  inch,  but  there  were  no  leaks.  The  pressure  was 
increased  up  to  a  maximum  of  22^  pounds  per  square 
jji  inch  without  leakage,  but  upon  examination  showed  that 


32 


SPOT  AND  ARC  WELDING 


some  of  the  spot  welds  on  the  stiff eners  had  given  away. 
The  structure  had  withstood  pressures  far  beyond  those 
required  for  this  service  and  the  tests  were  conclusive  as 
far  as  the  adoption  of  the  process  was  concerned. 

As  has  been  intimated  there  are  two  distinct  condi- 


FiG.  4. — Spot  welding. 


tions  under  which  riveting  is  done  in  shipbuilding:  that 
which  secures  the  principal  members  of  the  hull  struc- 
ture called  "field  riveting/'  and  accomplished  in  this 
country  by  a  group  of  men  in  which  one  man  uses  an 
air-driven  rivet  hammer,  and  that  which  is  done  in  the 
shops  by  semi-portable  machines.   These  latter  machines 


SPOT  WELDING 


33 


are  of  large  size,  usually  suspended  from  jib-cranes,  and 
are  portable  in  the  sense  that  they  may  be  brought  to  the 
work  and  moved  from  rivet  to  rivet  by  the  operator. 
These  portable  riveting  machines  are  equipped  with  air 
cylinders  and  connected  by  flexible  hose  to  a  common 
source  of  supply.  They  are  as  in  field  riveting  depen- 
dent upon  the  forge  fire  for  the  heating  of  the  rivet,  and 
on  the  rivet  boy  for  supplying  the  rivets  at  a  correct  tem- 
perature and  at  the  proper  time.  This  practice  in  ship- 
building shops  differs  from  that  in  bridge  shops  where 
the  machines  are  stationary,  usually  movmted  with  their 
jaws  in  a  vertical  position  and  to  which  the  overhead 
crane  brings  the  material  and  moves  it  for  the  continu- 
ous performance  of  riveting.  The  rapidity  with  which 
such  work  is  accomplished  in  this  latter  case  is  astonish- 
ing. A  close  study  of  this  problem  is  like  the  run  of 
spot-welded  work,  merely  requiring  as  much  time  and 
attention  devoted  by  those  who  understand  the  process 
as  has  been  given  by  those  who  understand  riveting.  In 
short,  it  is  a  qviestion  of  shop  production  which  in  the 
case  of  riveting  has  been  developed  to  a  high  state 
of  efficiency. 

All  these  points  and  many  more  suggested  that  spot- 
welding  machines  similar  to  a  pneumatic  riveting  ma- 
chine could  be  employed  with  advantage  in  shipbuilding 
and  would  hasten  the  construction  of  steel  ships.  The 
idea  was  proposed  to  convert  the  pneumatic  riveting  ma- 
chine as  now  used  into  spot-welding  machines  by  adding 
a  transformer  and  the  proper  flexible  connections.  This 
was  the  inception  of  the  design  of  two  machines  for  spot 
welding  which  were  built  for  the  Emergency  Fleet  Cor- 
poration of  the  U.  S.  Shipping  Board  and  with  which  a 


34 


SPOT  AND  ARC  WELDING 


practical  demonstration  was  made  the  early  part  of  last 
year.  The  builders  of  this  apparatus  had  previously  ex- 
perimented with  a  stationary  apparatus  of  large  size  to 
determine  if  there  were  any  obstructions  to  the  welding  of 
thick  steel  plates,  and  as  their  researches  showed  no  hin- 
drance to  the  process  up  to  the  spot  welding  of  three  | 
thicknesses  of  1-inch  boiler  plate,  they  accepted  an  order 
for  two  portable  spot  welders  and  one  stationary  spot 
welder  for  the  purpose  of  fabricating  the  steel  parts  for 
the  hull  structure  of  ships/  This  apparatus  will  be  fully 
described  in  connection  with  the  discussion  in  the 
next  chapter. 

There  were  men  who  desired  to  put  the  welding 
methods  to  test  in  shipbuilding,  for  the  emergency  was 
pressing,  and  yet  they  did  not  follow  the  English  ex- 
ample in  going  so  far  as  the  building  of  small  water 
craft.  The  English  Admiralty  built  in  the  early  part  of 
this  year  (1918)  a  cross-channel  barge  entirely  arc 
welded,  and  the  results  of  this  craft  were  and  are  well 
known  in  this  country.  It  was  decided  to  make  a  dem- 
onstration of  a  large  portion  of  the  middle  body  of  one 
of  the  standard  steel  ships  building  for  the  Emergency 
Fleet  Corporation.  The  scaffolding  for  this  work  was 
erected,  the  raw  material  delivered,  and  a  five-foot-gap 
portable  spot  welder  was  ordered  and  delivered.  The 
demonstration  as  planned  was  abandoned  after  the  sign- 
ing of  the  Armistice.  The  portable  spot  welder  was  sent 
to  the  same  shop  as  the  other  spot-welding  machines 
and  was  tested  as  a  part  of  the  demonstration  of 
spot  welding. 

^ "  Research  in  Spot  Welding  of  Heavy  Plates,"  W.  L.  Merrill,  General 
Electric  Review,  December,  1918. 


SPOT  WELDING 


35 


Summary. — The  spot  welding  of  light  materials  has 
been  practiced  in  this  country  for  the  last  fifteen  years 
and  its  performance  not  only  has  guaranteed  a  success- 
ful product,  but  also  has  increased  production  and 


Fig.  5. — Spot-welded  W.  T.  door  under  test  20  lbs.  per  square  inch. 


profits.  It  is  safe  to  state  that  its  extended  service  in 
those  industries  that  find  a  use  for  it  assure  its  future. 
For  the  joining  of  light  sheet  steel  it  has  no  competitor, 
but  for  the  softer  metals  the  process  has  not  been  suc- 
cessfully developed.   There  are  certain  alloys  that  may 


36 


SPOT  AND  ARC  WELDING 


be  welded  by  the  preparation  of  the  materials  or  by- 
changes  in  the  apparatus.  The  whole  subject  is  one  re- 
quiring investigation,  and  where  the  results  may  be  seri- 
ous attempts  should  not  be  made  without  thorough  tests. ^ 
As  stated,  copper  has  been  the  only  available  metal  found 
for  electrodes  and  any  metals  which  approximate  the 
current  carrying  capacity  of  copper  would  offer  no  re- 
sistance to  current  flow,  and  upon  this  principle  depends 
the  welding  heat. 

With  the  satisfactory  results  of  the  spot  welding  of 
thin  steel  sheets  placed  before  him  the  engineer  surmised 
that  the  process  was  capable  of  extension  to  heavier  steel 
structures.  The  industry  that  it  was  most  important  to 
aid  happened  to  be  that  of  shipbuilding,  but  the  prin- 
ciples of  the  application  are  suitable  to  all  manufactur- 
ing concerns  employing  heavy  steel  plates  and  shapes 
which  are  now  joined  by  rivets. 

In  shipbuilding  the  shop  rivets  are  used  to  connect 
and  assemble  small  parts  of  the  structure  and  for  the 
manufacturing  of  sub-structures.  The  field  riveting  is 
employed  to  put  the  assembled  materials  together  and 
form  the  completed  hull  of  the  ship.  The  shop  rivets 
are  driven  by  machines  brought  to  the  work  and  between 
the  jaws  of  which  the  rivet  is  squeezed.  The  field  rivet 
is  put  in  place  through  holes  punched  in  the  assembled 
parts  of  the  ship  structure  and  is  driven  by  a  hammer  on 
one  side  of  the  work,  actuating  against  a  pressure  ap- 
plied to  the  other  side  of  the  work.  The  main  question 
of  applying  spot  welding  to  the  entire  process  of  ship- 
building resolves  itself  into  two  possibilities.  There  can 
be  no  doubt  as  to  the  use  of  spot  welding  in  shop  work, 

^ "  Electric  Welding,"  Hamilton  and  Oberg,  p.  95. 


SPOT  WELDING 


37 


but  the  question  rises  whether  it  can  be  apphed  in  the 
field.  Either  great  developments  must  be  made  in  the 
spot-welding  tool  whereby  it  may  act  on  both  sides  of 
the  structure  without  interruption  to  other  work,  or  there 
must  be  prepared  special  designs  of  ship  and  shipyard 
whereby  the  spot-welding  tools  may  be  used.  That  is  to 
say,  that  the  welding  machines  would  not  be  required  to 
assume  shapes  and  sizes  that  militate  against  the  con- 
venient working  of  the  tool.  As  in  other  matters,  this 
last  possibility  is  one  for  cooperation  between  three  im- 
portant factors  in  shipbuilding:  the  owner,  the  naval 
architect,  and  the  shipbuilder.  There  is  always  an  ex- 
periment going  on  in  any  shipyard,  as  the  experienced 
shipbuilder  recognizes  that  every  ship  he  is  building  is  an 
experiment.  Perhaps  it  is  this  every-day  affair  that 
makes  the  shipbuilder  hesitate  to  accept  new  methods  for 
connecting  his  steel  ship.  The  shipbuilder  is  accustomed 
to  experimenting  and  when  he  discovers  the  benefits  to 
be  derived  by  the  adoption  of  spot  welding  he  will  be  its 
firmest  advocate. 


CHAPTER  IV 

Demonstration  of  Heavy  Spot  Welding 
(by  the  emergency  fleet  corporation) 

The  first  principle  laid  down  for  this  investigation 
was  that  it  should  be  practical  so  that  the  limitations  of 
practice  would  be  shown  in  high  relief.  That  these  limi- 
tations were  a  hindrance  to  a  full  report  of  the  ability  of 
the  apparatus  to  perform  in  a  certain  way  must  not  be  ||{ 
interpreted  as  a  detriment  to  the  process  nor  a  lack  of 
skill  upon  the  part  of  the  designer.  On  the  contrary, 
such  practical  handicaps  as  were  encountered  only  go  to 
prove  the  field  of  usefulness  and  the  profits  yet  to  be 
made  by  those  who  desire  to  invest  their  capital  in  a 
process  as  certain  as  the  results  of  this  demonstration 
showed.  No  theories  were  acted  upon  in  the  conduct- 
ance of  the  test  and  only  minor  modifications  were  made 
in  the  nature  of  developments  after  the  initial  trial  of 
the  first  machine.  The  results  of  the  tests  speak  well 
enough  to  assure  the  most  skeptical  of  the  safe  joining 
of  heavy  steel  members  by  the  spot-welding  process. 

Description  of  Apparatus. — Considering  the  adapt- 
ability of  the  machines  for  shipbuilding  service  it  was 
decided  to  build  three  machines,  two  semi-portable  of 
moderate  size  and  one  stationary  machine  of  large  size. 
The  semi-portable  welders  took, an  external  form  similar 
to  the  pneumatic  riveter  and  were  provided  with  bails  for 
attachment  to  cranes  for  facility  of  handling.  After  a 
careful  survey  of  the  usual  run  of  materials  in  the  plate 

38 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  39 


and  angle  shops  of  shipyards,  it  was  agreed  to  build  two 
sizes  of  portable  machines  to  cover  all  conditions  now 
met  with  in  practice.  The  smallest  machine  has  a  gap, 
or  throat,  capacity  for  reaching  over  a  width  of  12  inches 
and  the  other  a  gap  of  27  inches.  This  difference  in 
throat  not  only  increases  the  weight  due  to  the  additional 
frame  size,  but  also  adds  bulk  by  reason  of  the  trans- 
former capacity  which  must  be  greater  in  order  to  over- 
come the  reactance  caused  by  the  enclosing  of  a  large 
body  of  magnetic  material  in  the  electric  circuit.  Al- 
though much  care  was  given  to  the  lightening  of  the 
frame  and,  as  will  be  seen,  the  transformers  were 
made  remarkably  small  for  their  rated  capacity,  still 
these  machines  are  much  heavier  than  the  ordinary 
pneumatic  riveter. 

The  frames  of  these  portable  machines  were  cast  out 
of  gun  metal  to  provide  against  any  chance  of  a  react- 
ance sufficient  to  counteract  their  welding  qualities.  In 
what  may  be  termed  the  body  of  the  machine  a  recess  was 
left  for  the  transformer.  On  the  top  arm  was  located 
the  air  cylinder  for  providing  the  necessary  pressure  on 
the  electrodes.  The  under  body  portion  of  the  frame  was 
arranged  with  ample  projections  on  both  sides  so  that 
the  machine  could  be  bolted  down  in  place  and  used  as  a 
stationary  tool.  As  will  be  seen  from  Figs.  6  and  7,  the 
copper  electrodes  are  mounted  in  a  holder  insulated  from 
the  frame,  but  in  direct  line  with  the  pressure.  The  lower 
electrode  holder  is  bolted  directly  to  one  arm  of  the  sec- 
ondary of  the  transformer,  the  upper  electrode  holder  is 
connected  by  flexible  leads  of  laminated  copper  in  order 
to  permit  the  necessary  movement  for  squeezing  the  two 
pieces  of  work  together. 


40  SPOT  AND  ARC  WELDING 

The  maximum  air  pressm-e  provided  was  the  same 
for  both  machines.    The  air  cyhnder  was  8  inches  in 


FiQ.  6. — Electric  welder — 12"  reach — 60-265-440-8.45.   Capable  of  welding  together  two  steel  plates 
y^'  thick  in  spots  1"  in  diameter. 

diameter  and  attached  to  it  was  a  lever  arm  with  a  ratio 
of  5  to  1,  so  that  with  a  gauge  pressure  of  100  pounds 
per  square  inch,  25,000  pounds  per  square  inch  could.be 
exerted  on  the  work.  During  all  the  tests  this  was  never 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  41 


Fig.  7.— Electric  welder,  27"  reach— 60-350-440  =  11.25.    Capable  of  welding  together  two  steel 
plates  y%"  thick  in  spots  1"  in  diameter. 


obtained,  but  good  welding  was  accomplished  at  70-  and 
75-pound  gauge,  representing  17,500  and  18,750  pounds 
per  square  inch  on  the  work.   A  gauge  was  installed  on 


42 


SPOT  AND  ARC  WELDING 


the  air  line  for  the  purpose  of  checking  the  pressures  at 
all  times.  A  reducing  valve  was  also  provided,  so  that 
the  test  conditions  could  be  changed  and  variations 
allowed  for  thinner  material. 

There  are  many  interesting  points  of  design  in  con- 
nection with  these  two  machines  which  can  receive  only 
brief  mention.  One  of  them  is  the  transformer.  Per- 
haps no  transformers  were  ever  designed  or  built  within 
so  small  a  space  and  with  so  great  a  capacity.  The 
designer  for  this  alone,  to  say  nothing  of  the  successful 
operation  of  the  machine,  should  feel  proud.  The  capac- 
ity of  the  transformer  for  the  12-inch  machine  at  440 
volts  60  cycles  is  265  kv-a,  and  for  the  27-inch  machine 
at  the  same  voltage  and  cycles  350  kv-a.  In  the  large 
stationary  machine  there  are  two  transformers  of  450 
kv-a  each  at  500  volts  60  cycles,  and  the  over-all  dimen- 
sions are  11  inches  by  16  inches  by  18  inches.  The  nature 
of  the  work  done  as  well  as  a  resort  to  water-cooling  en- 
ables this  reduction  in  transformer  size.  The  making  of  a 
spot  weld  takes  a  few  seconds.  The  current  is  used  almost 
instantaneously.  The  primary  windings  are  made  of  cop- 
per tubing  specially  prepared  for  this  purpose,  and  the 
single-turn  secondary  was  built  of  copper  plates  bent  to 
shape  and  fitted  over  each  other  in  such  a  way  that  a 
passage  was  left  for  the  circulation  of  cooling  water. 

Another  interesting  point  of  design  is  that  connected 
with  the  electrodes.  As  stated  before,  copper  seems  to 
be  the  best  available  material  for  this  purpose,  and  its 
use  has  astonished  those  acquainted  with  metals,  for  it  is 
so  much  softer  than  the  steel  which  it  welds.  The 
severity  of  the  conditions  to  which  the  tips  of  the  elec- 
trodes are  subjected  will  be  understood  when  it  is  con- 


DEMONSTRATION  OP  HEAVY  SPOT  WELDING  43 


sidered  that  the  current  density  in  the  electrode  material 
at  this  point  is  approximately  60,000  amperes  per  square 
inch,  and  that  this  material  is  in  contact  with  the  steel 
plates  which  are  brought  to  the  welding  temperature, 
under  pressures  of  15,000  to  20,000  pounds  per  square 
inch.  It  must  be  remembered,  also,  that  copper,  which 
is  the  best  material  for  this  purpose,  softens  at  a  tem- 
perature considerably  lower  than  the  welding  tempera- 
ture of  steel.  The  difficulty  of  making  the  electrode  tips 
stand  up  under  the  conditions  to  which  they  are  sub- 
jected has,  in  fact,  constituted  the  most  serious  problem 
which  has  been  met  in  the  development  of  these  ma- 
chines." ^  This  question  has  been  practically  dealt  with 
by  providing  caps  and  separable  tips  for  the  electrodes 
as  well  as  by  maintaining  a  free  circulation  of  water 
through  the  electrode.  This  matter  will  be  further  dis- 
cussed when  considering  the  results  of  tests. 

Although  these  machines  could  be  properly  operated 
directly  from  a  440-volt  60-cycle  alternating-current 
source,  they  are  provided  with  auxiliary  transformers 
and  panels  for  regulating  the  voltage  and  current.  This 
allows  for  a  wide  range  of  work  and  permits  great  free- 
dom for  experimentation.  The  regulating  transformer 
panel  also  contains  a  contactor  for  the  ease  of  operation 
at  the  spot  welder  where  it  is  only  necessary  to  work  a 
hand  lever  for  the  mechanical  pressure  and  a  tripping 
switch  to  actuate  the  contactor  on  the  transformer  panel. 
The  contactor  functioning  as  a  thro  wing-in  switch  for 
completing  the  electrical  circuit  whereby  the  high  cur- 
rent passes  through  the  electrodes  producing  the  local- 

^ Recent  Developments  in  Machines  for  Electric  Spot  Welding,"  J.  M. 
Weed,  General  Electric  Revievi,  December,  1918. 


44 


SPOT  AND  ARC  WELDING 


ized  welding  temperature.  This  arrangement  of 
connections  permits  the  selector  panel  to  be  placed  re- 
motely from  the  spot- welding  machine,  thus  allowing 
freedom  for  movement  from  spot  to  spot. 

The  large  stationary  machine  was  built  with  a  6-foot 
throat,  so  that  it  could  reach  the  width  of  the  usual 
run  of  plates  used  in  shipbuilding,  and  as  was  thought 
at  the  time  of  designing,  would  be  able  to  fabricate  com- 
plete deck  houses  as  well  as  join  two  steel  plates  of 
inch  thickness.  In  order  to  reduce  the  great  capacity 
that  would  be  required  to  overcome  the  effects  of  react- 
ance in  this  case,  the  designer  did  two  skilful  things.  He 
provided  two  transformers,  two  pairs  of  electrodes,  thus 
doubling  the  number  of  spots  per  operation,  and  then 
disposed  the  transformers  one  on  each  side  of  the  work, 
thus  reducing  the  reactance  to  a  minimum.  Incidentally 
this  allowed  the  use  of  steel  for  the  frame  which  was 
constructed  of  two  steel  plates  each  two  inches 
thick.  Gun  metal' was  used  for  the  heads  carrying  the 
copper  electrodes. 

Fig.  8  illustrates  this  machine,  showing  that  the  same 
arrangement  of  connecting  the  upper  and  lower  elec- 
trode holder  to  the  secondaries  of  the  transformers  was 
employed.  The  same  general  features  of  design  are 
carried  out  on  a  larger  scale.  The  air  pressure  is  in- 
creased to  a  maximum  of  30,000  pounds  per  square  inch 
on  each  cylinder.  There  are  two  cylinders  provided,  so 
that  each  pair  of  electrodes  may  be  separately  operated 
and  also  to  obtain  successful  spots  when  making  two 
welds  simultaneously.  The  air  cylinders  are  located  in 
the  body  of  the  machine  and  operate  through  7-foot 
levers  to  the  electrodes. 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  45 


The  electrodes  are  arranged  to  be  easily  removed 
and  may  be  shifted  on  their  bases  to  positions  of  90 
degrees,  so  that  the  spots  may  be  made  in  line  with  the 
axis  of  the  machine  or  transversely.   The  electrodes  are 


Fig.  8— Duplex  electric  welder  —  6  ft.  reach.    2  (60-400-'220-7.86) .     Capable  of  welding  together 
two  steel  plates        thick  in  two  spots  1 M"  in  diameter. 

spaced  8  inches  centre  to  centre,  but  may  be  disposed 
from  10  to  6  inches  centre  to  centre. 

The  cooling  of  the  electrodes  as  well  as  the  cooling 
of  the  transformer  winding  is  similar  to  that  of  the 
smaller  machines.   Hydrant  water  has  been  found  prac- 

i    tical  for  this  purpose.    The  water  traverses  the  appa- 
ratus in  two  parallel  paths,  "  one  being  through  the 

I    primary  winding  and  the  other  through  the  secondary 


46 


SPOT  AND  ARC  WELDING 


and  the  electrodes  in  series."  ^  Separate  valves  are  pro- 
vided for  independent  control  of  flow  in  the  two  paths. 

This  duplex  spot  welder,  as  it  is  called,  is  capable  of 
producing  50,000  amperes  with  500  volts  60  cycles. 
With  this  much  current  in  the  secondaries  the  current 
in  the  primaries  is  1800  amperes.  The  kv-a  under  these 
conditions  is  450  for  each  transformer,  and  at  440  volts 
and  the  same  cycles  kv-a  will  be  approximately  350. 

As  with  the  smaller  machines  the  6-foot  duplex 
machine  may  be  operated  on  a  440-volt  60-cycle  alter- 
nating-ciuTcnt  source  of  supply,  but  a  regulating  trans- 
former was  provided  for  the  purpose  of  connecting  these 
machines  to  a  higher  voltage  supply  as  well  as  to  regu- 
late the  voltage  and  current  for  different  thicknesses  of 
material  for  experimental  purposes.  The  capacity  of 
the  transformer  supplied  was  350  kv-a,  and  as  was  just 
stated,  this  machine  required  at  least  350  kv-a  at  440 
volts  on  each  welding  transformer — a  total  of  700  kv-a. 
The  apparent  discrepancy  is  removed  when  it  is  remem- 
bered that  the  operation  is  in  seconds,  a  period  of  over- 
load too  short  to  injure  the  transformer.  More  interest- 
ing is  the  physical  difference  in  size  between  this  350 
kv-a  regulating  transformer  and  one  of  the  transformers 
of  the  duplex  spot  welder. 

On  the  regulating  panel  is  mounted  the  contactor 
for  connecting  the  electrical  supply  to  the  two  trans- 
formers and,  as  will  be  seen  in  Fig.  8,  the  remote  control 
switch  for  actuating  the  contactor  is  mounted  in  a  group 
with  the  air  levers  and  air  gauges.  The  entire  mechan- 
ism is  controlled  from  this  point  and  with  a  nicety  that 

^ Recent  Developmentsi  in  Machines  for  Electric  Spot  Welding,"  J.  M. 
Weed,  General  Electric  Review,  December,  1918. 


DEMONSTRATION  OP  HEAVY  SPOT  WELDING  47 


reflects  much  credit  to  its  builders.  From  this  position 
both  electrodes  may  be  raised  or  lowered  independently 
or  together,  and  by  placing  a  spacing  block  of  copper 
between  one  of  the  pairs  of  electrodes  the  other  electrode 
may  be  used  to  make  a  single  spot.  This  is  often  of 
advantage  in  working  along  a  seam,  as  the  multiple  of 
two  may  not  meet  the  requirements  of  the  adopted  spac- 
ing, so  that  it  may  be  necessary  to  make  a  single  spot  to 
complete  the  job. 

These  machines  are  equipped  with  all  the  best  and 
latest  features  of  good  design.  The  workmanship  is 
excellent  and  the  materials  well  calculated  to  endure  the 
heavy  duty  that  should  come  to  this  machine  in  regular 
production  work.  Intrinsically  the  machine  is  of  high 
value  and  is  self-contained;  extrinsically  this  machine 
for  commercial  production  will  probably  require  an 
auxiliary  that  will  change  the  frequency  of  the  electric 
supply,  distribute  the  power  as  now  supplied  over  the 
three  phases,  and  reduce  the  sudden  rushes  of  current 
required  by  the  process.  As  has  been  described  of  this 
apparatus,  it  all  operates  on  a  single-phase  current  and 
at  60  cycles.  Under  these  conditions  there  is  a  large 
unbalance  to  be  expected  in  the  supply  as  well  as  in  the 
low-power  factor.  By  means  of  proper  auxiliary 
apparatus  the  power  consumed  as  well  as  the  other 
desirable  features  mentioned  may  be  obtained,  and  this 
apparatus  will  then  function  well  within  the  bounds  of 
commercial  economics. 

Specified  Requirements. — When  the  orders  were 
issued  for  this  apparatus  this  previous  consideration  was 
probably  never  entertained  because  it  was  not  estimated 
that  these  three  machines  would  be  in  simultaneous  use. 


48 


SPOT  AND  ARC  WELDING 


If  such  had  been  the  case  some  form  of  apparatus  to 
correct  the  electrical-supply  conditions  would  have  been 
required.  It  was  thought  that  the  work  of  these  ma- 
chines was  so  rapid  that  even  our  largest  shipyard,  Hog 
Island,  for  which  these  machines  were  ordered,  would 
fail  to  supply  them  with  as  much  work  as  they  could  per- 
form. And  this  would  have  been  true  unless  great 
changes  in  the  methods  of  building  ships  had  come  to 
pass.  These  machines  were  never  completely  delivered 
or  operated  at  Hog  Island,  but  were  diverted  for  dem- 
onjstration  purposes  to  one  of  the  many  bridge  shops 
which  were  fabricating  material  for  the  shipyard.  This 
work  being  in  line  with  strict  production  output  these 
machines  were  more  suitable,  and  their  introduction  was 
interrupted  solely  because  of  the  Armistice. 

Some  of  the  detail  requirements  of  this  apparatus 
had  to  conform  to  the  electrical-supply  conditions  of  Hog 
Island,  so  that  the  regulating  transformers  were  all  fur- 
nished for  a  primary  voltage  of  2200,  single-phase,  60- 
cycle  alternating  current.  As  the  electrical  current  at 
the  Island  was  also  distributed  on  a  low- voltage  (440) 
system  at  60  cycles  the  transformers  integral  with  the 
welding  machines  were  so  specified.  These  points  were 
common  to  all  the  machines. 

The  6-foot-throat,  duplex,  spot- welding  machine  was 
required  as  a  maximum  of  capacity  to  weld  two  spots  at 
once  through  two  thicknesses  of  ^-inch  steel  plate,  i.e., 
it  was  to  be  capable  of  welding  continuously  two  thick- 
nesses of  j^-inch  steel  and  two  welds  at  each  operation. 
No  particular  ship  work  was  specified  nor  any  require- 
ments conditioned  upon  the  efficiency  of  the  spot-welded 
joint  as  compared  to  the  customary  methods  of  riveting. 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  49 


In  the  same  way  the  12-  and  27-inch  welding  machines 
were  required  as  the  maximum  of  work  to  weld  two 
thicknesses  of  ^-inch  steel  plate  without  further  stipu- 
lation as  to  performance.  Other  requirements  referred 
to  the  special  features  described  above  and  appurte- 
nances, such  as  flexible  leads  for  the  portable  machines, 
transformers,  panels,  remote-control  switches,  water- 
cooling  arrangements,  etc. 

The  point  to  be  noted  is  that  in  all  fairness  to  the 
builders  this  specification  was  their  responsible  guide 
and  legal  guarantee.  No  more  could  be  sought  in  an 
acceptance  test,  which  was  the  real  purpose  of  this  dem- 
onstration, than  that  these  machines  would  securely  weld 
two  thicknesses  of  ^-inch  steel  plate  in  the  case  of  the 
two  semi-portable  and  two  thicknesses  of  the  ^-inch 
steel  plate  in  the  case  of  the  duplex  welder.  It  is  esti- 
mated roughly  that  80  to  90  per  cent,  of  riveted  ship 
joints  are  three  thicknesses,  and  approximately  15  to  20 
per  cent,  four  thicknesses  of  steel  plate.  The  question 
then  arises.  Are  these  machines  suitable  for  ship  construc- 
tion? It  is  not  altogether  possible  to  carry  the  demon- 
stration to  an  unequivocal  answer  in  the  affirmative,  but 
it  is  believed  that  the  many  tests  made,  remembering  the 
limitations  under  which  they  were  conducted,  show  that 
these  machines  would  give  a  satisfactory  performance 
for  ship  fabrication  under  favorable  shop-production 
management.  It  should  be  borne  in  mind  in  looking 
critically  at  the  results  that  the  responsibility  of  those 
interested  in  this  demonstration  ceased  when  the  require- 
ments  of  the  specifications  were  fully  met. 

Arrangements  for  Tests. — The  bridge-construction 
j!  company,  which  was  one  fabricating  ship  material  for 

4 


Fia.  9. — Oil  switches  and  high  potential  in-coming-line  panel  for  spot-welding  demonstration. 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  51 


the  Hog  Island  shipyard,  selected  for  the  demonstra- 
tion was  the  McClintic-Marshall  Construction  Co.,  lo- 
cated at  Pottstown,  Pa.  At  the  time  of  preparation 
for  the  tests  the  new  Liberty  Shop,  devoted  entirely  to 
ship  fabrication,  was  just  nearing  completion.  It  was 
decided  to  erect  the  apparatus  in  this  shop  in  one  of  the 
bays  designed  for  a  group  of  riveting  machines  with  the 
intention  of  retaining  them  in  this  production  position  if 
all  went  well.  This  location  gave  easy  access  to  air  and 
water  supply  and  avoided  interference  with  other  sec- 
tions of  work  in  the  shop. 

At  a  high  point  near  the  roof  a  temporary  platform 
was  built  with  head-room  for  the  incoming-line  panels, 
oil  switches,  and  the  regulating  transformers  for  the  12- 
and  27-inch  semi-portable  machines.  Fig.  9  shows  the 
arrangement  of  this  apparatus  which  secured  safety  by 
keeping  the  high  potential  away  from  the  working 
spaces.  Fig.  10  illustrates  the  mounting  of  the  regulat- 
ing transformers  for  the  semi-portable  machines.  The 
electric  conductors  were  carried  down  in  a  vertical  line 
from  these  transformers  to  a  second,  or  lower,  temporary 
platform  upon  which  were  placed  the  selector  panels. 
Upon  these  panels  were  placed  the  remotely  controlled 
contactors.    This  is  clearly  seen  in  Fig.  11. 

This  same  illustration  shows  the  electrical  connec- 
tions from  the  selector  panels  to  the  two  machines.  On 
the  left-hand  side  is  the  27-inch  welder  and  on  the  right 
is  the  12-inch.  The  leads  which  look  like  hose  in  the 
photograph  are  electric  wires  which  close  the  contactors 
which  in  turn  energize  the  machine  transformers  from 
which  the  secondary  or  induced  current  is  obtained  for 
producing  the  welding  current.    The  large  dark  leads 


52 


SPOT  AND  ARC  WELDING 


are  the  wires  which  carry  the  main  primary  current  from 
the  taps  on  the  selector  panels.  It  will  be  seen  from  the 
photogi^aph  that  the  taps  on  the  panels  are  numbered 
starting  on  the  left-hand  upper  row  and  by  means  of 


Fig.  10. — Regulating  transformers  for  12"x  27"  semi-portable  spot-welding  machines. 


two  removable  sliding  contacts  a  varied  combination  of 
connections  may  be  made. 

In  this  same  Fig.  11  on  the  right-hand  side  will  be 
seen  the  water  supply  and  exhaust  for  the  cooling  sys- 
tem for  the  12-inch  machine.  These  connections  are 
made  at  the  lower  back  end  of  the  frame  just  inside  of 
which  is  the  transformer.  Almost  in  a  direct  vertical 
hne  will  be  seen  the  air  connections,  reducing  valve,  and 


DEMONSTRATION  OP  HEAVY  SPOT  WELDING  53 


air  gauge.  The  photograph  incidentally  shows  the  12- 
inch  machine  spot  welding  a  part  of  one  of  the  samples 
used  in  the  demonstration  and  to  be  described  later. 

This  particular  photograph  was  taken  very  shortly 
after  the  apparatus  was  installed,  and  at  that  time  it  was 


Fig.  11. — Selector  panels  for  H"x  27"  semi-portable  spot-welding  machines. 

anticipated  that  the  machine  would  be  operated  as  port- 
able tools.  A  sufficient  attempt  was  made  to  do  this, 
but  it  was  quickly  discovered  that  the  shop  did  not 
have  the  requisite  crane  facilities  for  permitting  this 
arrangement  as  a  regular  method.  These  machines  were 
then  transferred  to  the  other  side  of  the  steel  columns 
and  made  stationary  on  steel  horses.    This  gave  perma- 


SPOT  AND  ARC  WELDING 


nency  to  the  machines  and  served  the  purpose  of  the 
tests,  although  it  required  very  awkward  and  detrimental 
handling  of  large  bulky  pieces  to  the  machines.  This 
latter  arrangement  of  the  small  miachines  can  in  part  be 
seen  in  Fig.  12  to  the  left  of  the  large  6-foot  duplex 
spot  welder. 

This  same  illustration  indicates  the  size  of  the  6-foot 


Fig.  12. — Six-foot  duplex  spot-welding  machine  in  place  for  tests. 

duplex  spot  welder,  and  shows  distinctly  the  electrodes 
with  cooling-water  connections  and  the  arrangement  for 
replacing  the  electrode  tips.  As  the  regulating  trans- 
former (Fig.  13)  for  this  machine  was  too  great  in 
height  and  weight  for  the  temporary  platform  already 
supporting  the  two  regulating  transformers  for  the  small 
machines,  it  was  placed  as  shown  on  the  main  shop  floor 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  55 

just  back  of  the  spot  welder.  To  one  side  of  it  was 
located  the  selector  panel  (Fig.  14)  containing  also  the 


Fig.  13. — Regulating  transformer  for  six-foot  Fig.  14. — Selector  panel  for  six-foot  spot- 

spot-welding  machine,  in  place  for  testmg.  welding  machine  in  place  for  testing. 


main  switch  contactor.  This  arrangement,  although 
necessitating  a  continuation  of  the  high-potential  leads 


56 


SPOT  AND  ARC  WELDING 


to  the  floor  of  the  shop,  permitted  short  connecting  leads 
between  the  transformer,  panel  and  machine.  The  high- 
potential  leads  were  carefidly  protected.  The  whole  lay- 
out was  of  a  temporary  nature,  due  to  delay  in  the  de- 
livery of  this  machine  and  the  fact  that  the  time  allotted 
for  this  demonstration  was  drawing  to  a  close. 

In  the  same  space,  but  a  little  farther  down  the  shop, 


Fig.  15. — Five-foot  portable  spot  welder  in  place  for  tests. 


was  placed  the  5-foot  portable  spot  welder  (Fig.  15) 
which  was  intended  for  use  in  building  the  demonstra- 
tion section  of  a  middle  body  portion  of  a  standard  ship. 
Through  the  large  gap  may  be  seen  the  27-inch  semi- 
portable  spot  welder,  and  to  the  extreme  right  the  rear 
or  control  end  of  the  6-foot  duplex  spot  welder.  This 
photograph  gives  the  appearance  of  great  bulk  and 
weight  to  the  machine,  but  the  castings  were  lightened  in 
great  measure  and  with  a  sufficiently  powerful  crane 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  57 


and  proper  rigging  this  5-foot  spot  welder  could  prob- 
ably be  handled.  The  head,  as  will  be  seen,  was  fitted 
with  a  pair  of  short-circuiting  electrodes  and  a  pair  for 
making  the  weld.  These  copper  electrodes  were  about 
three  inches  in  diameter  and  the  intention  was  to  use  a 
copper  button  on  each  side  of  the  joint  to  be  welded. 
There  were  no  mechanical  arrangements  for  holding 
these  buttons  in  place  in  case  the  machine  had  to  be  tipped 
to  make  the  weld,  but  presumably  it  was  intended  that 
the  buttons  would  be  held  in  place  by  the  operator  or  one 
of  his  assistants.  Back  of  the  hinge  can  be  seen  the  air 
cylinder  and  piston  which  provided  the  mechanical  pres- 
sure on  the  electrodes.  Just  above  this  cylinder  and  en- 
closed in  the  upper  arm  was  a  small  electric  motor  for 
close  adjustment  of  the  jaws.  The  welding  transformers 
were  enclosed  in  the  casing  just  back  of  the  head  near 
which  on  the  opposite  side  from  that  shown  was  placed 
the  operating  switch.  This  control  switch  combined  the 
movements  of  the  jaws  and  the  operation  of  the  main- 
line switch  through  the  remote  contactor  which  as  in  the 
other  designs  was  placed  on  a  panel  at  some  distance 
from  the  machine.  This  spot  welder  was  not  provided 
with  means  for  changing  the  supply  voltage,  but  oper- 
ated on  a  220-volt  60-cycle  single-phase  alternating  cur- 
rent. This  supply  voltage  was  taken  from  a  suitable 
tap  from  one  of  the  regulating  transformers  of  the 
other  machines. 

The  high-potential  line  was  brought  from  the  main 
power-house  of  the  plant  which  in  turn  was  served  by  the 
local  central  station.  Every  precaution  was  taken  as  re- 
gards the  effects  that  might  be  occasioned  on  these  lines. 
The  central-station  company  was  fully  informed  as  to 


58 


SPOT  AND  ARC  WELDING 


the  experiments  to  be  made  and  the  amount  of  energy 
that  would  be  suddenly  demanded.  Additional  central- 
station  transformers  were  at  hand  in  case  they  should  be 
needed.  No  difficulties  as  to  power  supply  were  encoun- 
tered during  the  trials  of  the  small  machines,  and  the 
voltage  drop  at  this  period  of  the  demonstration  was  not 
excessive.  It  was  not  necessary  to  operate  both  these 
machines  together,  and  so  this  was  never  done.  When 
the  6-foot  duplex  machine  was  first  tried  the  voltage  drop 
was  very  great  and  additional  copper  conductors  were 
installed  with  available  material.  This  reduced  the  volt- 
age drop  an  appreciable  amount,  but  not  to  a  point  which 
would  give  the  maximum  capacity  of  this  machine.  The 
time  for  correcting  this  limitation  would  greatly  exceed 
that  permitted  for  these  tests  and  it  was  considered  in- 
expedient to  expend  further  time  and  money  in  view  of 
the  fact  that  this  machine  had  shown  itself  fully  capable 
of  meeting  the  specification  requirements,  and  undoubt- 
edly with  a  full  voltage  supply  would  have  greatly  ex- 
ceeded them.  The  results  in  the  opinion  of  those  most 
concerned  testified  to  the  reasonableness  of  the 
action  taken. 

Methods  and  Procedure  of  Tests. — In  view  of  the 
broad  interest  taken  by  Lloyd's  Register  of  Shipping  in 
the  application  of  electric  welding  to  steel  ship  construc- 
tion and  the  recent  investigations  of  this  classification 
society  into  the  processes  of  arc  welding  which  were  con- 
ducted in  England,  it  was  deemed  appropriate  to  parallel 
some  of  the  smaller  practical  tests  for  the  sake  of  com- 
parison. One  of  these  tests  was  designed  to  compare  the 
bearing  value  of  a  short  attachment  lug  riveted  as  against 
arc  welded.   This  same  design  was  used  but  the  attach- 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  59 


ment  lug  was  spot  welded  with  the  same  number  of  spots 
as  rivets.  The  test  pieces  consisted  of  %-inch  flat  plate 
6  inches  wide  by  18  inches  long  upon  which  was  riveted 
an  angle  lug  2^^  by  2)^  by  ^  inches.  The  lug  was 
secm-ed  to  the  plate  by  four  ^-inch  rivets  spaced  2^^ 
inches  centre  to  centre.  The  attachment  lug  was  12 
inches  in  length.  In  the  spot-welded  test  piece  four 
spots,  located  as  nearly  as  possible  to  the  same  spacing, 
secured  the  same-sized  angle  lug.  This  sample  repre- 
sents a  very  frequent  job  in  the  fitting-up  of  the  hull  of 
a  ship  and  the  practical  value  of  the  comparison  can- 
not be  questioned. 

The  second  test  piece  was  intended  in  the  Lloyd's 
investigations  to  compare  "  the  relative  value  of  welding 
and  caulking  under  tension."  ^  In  the  case  of  the  spot- 
welding  comparison  this  was  at  first  not  considered, 
although  a  sample  of  spot-  and  arc- welded  joint  was 
later  made  with  results  that  were  easily  foretold.  This 
test  piece  took  the  shape  of  a  cross  and  simulated  the 
boundary  of  a  water-tight  compartment.  It  consisted 
of  a  20-pound  flat  plate  24  inches  long  and  about  15^ 
inches  wide.  At  the  centre  of  this  plate  and  perpen- 
dicular to  it  were,  attached  by  3^  X  3^  X  %-inch 
angles,  two  flat  plates  24  inches  long  and  7^  inches 
wide.  The  %-inch  angles  were  first  secured  to  the  two 
small  pieces  of  20-pound  plate  by  ten  ^-inch  rivets, 
and  then  the  two  angles  joined  by  the  same  number  and 
size  of  rivets  to  the  large  flat  plate.  This  required  the 
joining  of  three  thicknesses  of  material  amounting  to  a 
total  thickness  of  two  inches.    The  spot-welded  test 

^ "  Lloyd's  Experiments  on  Electrically-Welded  Joints,"  H,.  J,  Cox, 

General  Electric  Reiriew,  December,  1918. 


60 


SPOT  AND  ARC  WELDING 


pieces  were  made  up  in  the  same  manner  and  secured  the 
members  with  ten  evenly  spaced  spot  welds.  As  much 
difficulty  was  encountered  not  only  with  modifications 
of  the  then-available  spot-welding  machine,  but  also  with 
the  testing  machine,  and,  as  the  ^-inch  angles  of  this 
piece  were  in  excess  of  practice  for  such  a  connection, 
the  spot-welded  test  pieces  were  afterwards  changed  to 
X  3^  X  J^-inch  angles.  During  the  trials  certain 
other  test  pieces  were  prepared  and  tested  in  order  to 
determine  the  proper  proportion  of  current,  time,  etc., 
needed  for  spot  welding  three  thicknesses  of  ^^-inch  steel 
plate.  These  test  pieces  consisted  of  two  strips  of  size 
convenient  for  the  testing  machine  placed  end  to  end  and 
the  joints  covered  by  a  small  strip  top  and  bottom.  This 
allowed  two  spots  through  three  thicknesses  of  ^-inch 
steel,  a  total  thickness  of  1^  inches. 

This  practice  of  spot  welding  three  thicknesses  was 
of  value  in  the  next  undertaking  which  was  the  spot  weld- 
ing of  a  ship's  floor.  Fig.  16  shows  the  floor  in  process 
of  spot  welding.  This  job  is  in  line  with  regular  produc- 
tion work.  In  order  to  make  comparison,  material  was 
prepared  for  three  sets  of  floors.  One  of  these  was  to  be 
riveted  in  the  usual  manner,  the  next  was  to  be  arranged 
with  a  few  holes  punched  for  assembling  and  then  to  be 
spot  welded,  and  the  third  was  simply  the  materials  cut 
ready  to  be  spot  welded.  In  the  latter  case  the  materials 
were  assembled  by  arc-weld  tacking.  When  these  floors 
were  ready  for  test  only  one  spot- welding  machine  was 
available,  the  small  12-inch  machine.  An  accident  had 
happened  to  the  27-inch  welder  and  the  6-foot  duplex 
machine  was  not  ready  for  shipment.  In  addition,  modi- 
fications to  the  electrodes  of  this  machine  were  necessary 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  61 

both  in  order  to  weld  through  three  and  four  thicknesses 
of  20-pound  plating,  and  also  in  order  to  manipulate  the 
apparatus  so  as  to  locate  the  spots  in  the  proper  position 
with  respect  to  the  heel  of  the  bounding  angle.  These 
floors  were  spot  welded  with  only  two  points  in  mind. 


Fig.  16. — Spot- welded  ship  floor. 

both  of  which  were  clearly  demonstrated :  (1)  That  spot 
welding  along  a  certain  circumscribed  seam  would 
neither  distort  nor  elongate  the  material,  i.e.j,  cause  a 
creeping  effect ;  ( 2 )  that  the  edge  of  the  angle  resting  on 
the  flat  plate  would  not  be  scored  nor  distorted  to  the 
detriment  of  the  mechanical  caulking,  i.e.,  that  a  caulk- 
ing edge  would  be  preserved.  That  the  spot  welding  of 
these  floors  also  showed  other  features  that  were  fair 


62 


SPOT  AND  ARC  WELDING 


must  be  considered  without  the  intent  or  purpose  of  the 
test ;  that  the  floors  did  not  meet  with  a  full  success  when 
subjected  to  later  tests  was  to  be  expected. 

Historically  considered  the  demonstration  had  now 
reached  a  point  where  more  practical  data  was  desired. 
The  27-inch  semi-portable  machine  had  been  repaired 
and  was  now  set  up  with  modifications  principally  in  the 
protection  of  the  electrodes.    This  machine  as  mounted 
and  modified  was  found  more  convenient  for  the  next 
series  of  tests,  although  the  12-inch  machine  with  similar 
modifications  would  have  produced  like  results.  The 
test  pieces  now  prepared  were  varying  thicknesses  of 
steel  plate  from  ^  inch  to  ^  inch,  i.e.,       }i,  and 
%  inch.    The  pieces  were  ten  feet  long  and  of  a  width 
suitable  for  easy  handling  in  the  tensile- testing  machine. 
These  strips  of  plating  were  lapped  and  tacked  together 
by  means  of  the  electric  arc.    Continuous  spots  were 
made  at  a  spacing  which  would  permit  of  the  cut  samples 
entering  the  jaws  of  the  testing  machine.    The  spots 
were  made  in  various  ways  to  detect  any  gain  or  loss  by 
the  order  in  which  the  spots  were  made.  After  the  plates 
were  spot  welded,  each  spot — about  thirty  for  each 
10-foot  plate — was  cut  by  means  of  the  oxy-acetylene 
flame,  then  pulled  in  an  Olsen  tensile-testing  machine. 
These  tests  were  made  to  demonstrate  the  uniformity  of 
work  that  might  be  expected  in  regular  practice  and  to 
determine  to  what  extent  the  operator  or  the  machine 
entered  into  the  problem.    As  will  be  seen,  the  results 
are  very  clear  on  these  points. 

To  convince  those  who  might  feel  that  spot  welding 
would  not  be  able  to  withstand  the  shocks  which  threaten 
the  destruction  of  a  ship  when  she  strikes  a  submerged 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  63 


rock,  a  sample  of  20-pound  plate  6  feet  long  and  24 
inches  wide  with  a  bounding  angle  3^  by  3^  by  7/16 
inches  was  spot  welded.  This  was  subjected  to  a  rough 
test  under  a  30-ton  steam  hammer.  The  highest  static 
pressure  that  the  hammer  could  exert  did  not  affect  this 
sample  while  placed  on  edge.  The  hammer  was  then 
raised,  the  sample  braced  on  the  angle  and  a  blow  de- 
livered. After  several  blows,  the  sample  being  returned 
to  the  same  relative  position  after  each  pounding,  the 
angle  on  the  top  edge  showed  fatigue.  The  sample  was 
then  turned  and  blows  repeated  at  different  positions  in 
the  length.  A  careful  examination  showed  that  where 
the  angle  had  broken  away  from  the  plate  the  welded 
joint  had  torn  the  original  metal  with  it.  This  sample 
showed  distortion  and  it  was  noted  how  tenaciously  the 
spot-welded  angle  clung  to  the  plating. 

As  a  sequel  to  the  uniformity  test  a  number  of 
shorter  test  pieces  were  made  up  of  20-pound  plating 
and  lapped  to  varying  widths,  spot  welded  with  two, 
three,  and  four  rows  of  spots.  These  tests  were  made 
as  a  comparsion  with  double-,  triple-,  and  quadruple- 
riveted  joints. 

These  latter  tests  with  the  uniformity  tests  on  ^-inch 
steel  plate  brought  the  demonstration  to  an  end.  The 
^-inch  uniformity  tests  could  be  made  only  on  the 
duplex  spot-welding  machine,  which  was  not  available 
until  near  the  conclusion  of  the  allotted  time.  It  was 
fortunate  that  this  series  of  tests  could  be  completed,  as 
it  furnishes  data  of  value  to  those  who  may  wish  to  go 
forward  with  this  process. 

Results  of  Tests. — Before  spot  welding  the  first  test 
pieces  of  20-pound  plating  it  was  essential  that  a  deter- 


64 


SPOT  AND  ARC  WELDING 


mination  of  the  time  for  welding  this  thickness  of  mate- 
rial be  obtained.  It  was  also  necessary  for  the  operator 
to  know  the  effects  of  the  different  voltage  taps.  Thirteen 
samples  were  spot  welded  with  a  single  spot  and  with 
varying  time  and  current.  These  samples  were  all  made 
on  the  12-inch  spot  welder  and  pulled  for  ultimate  ten- 

TABLE  I. 


Samples  for  Adjustment  of  Machine. 


Sample 
No. 

Open-circuit 
Voltage 

Welding 
Time 

Ultimate 
Load 

Remarks 

1 

560 

13 

40,600 

2 

560 

8 

30,600 

3 

360 

22 

20,100 

4 

410 

15 

20,800 

5 

455 

7 

36,700 

6 

455 

9 

36,600 

7 

455 

9 

35,600 

8 

407 

11 

43,000 

9 

460 

11 

45,300 

10 

510 

13 

45,100 

11 

510 

10 

43,600 

12 

510 

10 

40,400 

13 

510 

15 

73,100 

sile.  Table  I  gives  the  results  as  taken.  The  second 
column  is  the  voltage  reading  of  the  taps  on  this  selector 
panels  with  the  main  contactor  switch  open;  that  is,  no 
work  being  done.  The  drop  in  voltage  is  not  taken  into 
account.  The  last  sample  differed  from  the  others  in 
that  it  consisted  of  three  thicknesses  of  20-pound  plating. 
This  was  to  determine  the  conditions  for  welding  three 
thicknesses.  Fig.  17  gives  an  idea  of  the  appearance  of 
a  spot  weld  after  undergoing  shear  in  the  tensile-testing 
machine.  Fig.  18  illustrates  the  torsional  strains  suf- 
fered by  the  sample  while  under  tensile  puUing.  This 
is  caused  by  the  overlap  of  the  two  pieces,  throwing  the 
action  of  the  testing  jaws  off  centre. 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  65 


An  independent  set  of  electrical  readings  were  taken 
as  a  preliminary  step,  so  that  afterwards  results  might 
be  interpreted  from  them,  but  it  was  determined  that  the 
electrical  conditions  did  not  vary  to  a  point  detrimental 
to  the  welding  require- 
m  e  n  t  s.  Consequently, 
electrical  readings  were 
not  taken  in  every  in- 
stance. During  the  uni- 
formity tests  electrical 
readings  were  taken  as  a 
check  and  proved  the  cor- 
rectness of  this  decision. 
Table  II  gives  the  open- 
voltage  readings  across 
the  primary  winding  of 
the  12-inch  spot-welded 
transformer  when  t  h  e 
connections  on  the  se- 
lector panel  were  made  as 
indicated  by  the  nmnerals 
on  the  panel.  These  read- 
ings at  once  established 
the  practice  for  the  selec- 
tion of  the  taps,  and  so  by      Fig.  17— single  spot  weia  in  two  thicknesses  of 

trial  of  the  various  thick- 

nesses  of  stock  material  or  the  number  of  the  thicknesses 
required  to  be  welded,  the  open-circuit  voltage  was  ap- 
proximately known.  With  this  information  those  famil- 
iar with  the  electrical  design  could  estimate  the  amount 
of  current  passing  through  the  electrodes. 

For  a  full  investigation  into  the  electrical  conditions 
5 


66 


SPOT  AND  ARC  WELDING 


Fig.  18, — Shows  sample  weld  after  shearing  in  the  testing  machine.  Note  the  effect  of  torsional  strains. 


TABLE  II. 
Voltage  Tap  Readings. 


Connections 
Upper  Lower 

Voltage 

Connections 
Upper  Lower 

Voltage 

1  and 

5 

277 

3 

and  5 

375 

1  and 

6 

308 

3 

and  6 

407 

1  and 

7 

363 

3 

and  7 

455 

1  and 

8 

410 

3 

and  8 

505 

2  and 

5 

353 

4 

and  5 

427 

2  and 

6 

360 

4 

and  6 

460 

2  and 

7 

410 

4 

and  7 

510 

2  and 

8 

463 

4 

and  8 

560 

DEMONSTRATION  OF  HEAVY  SPOT  WELDING  67 


SEUCTOR  PANEL 


^   WELDER  ^ 


MULTIPLYER  4-  / 


CONNECTIONS  OF  TESTING  INSTRUMENTS 
Fig,  19. — Connections  of  testing  instruments. 


68 


SPOT  AND  ARC  WELDING 


it  was  decided  to  take  a  complete  set  of  readings.  In- 
struments were  introduced  into  the  circuit  as  shown  in 
Fig.  19  and  the  mean  of  four  readings  is  recorded  in 
Table  III.  These  readings  were  taken  under  load.  The 


TABLE  III. 
Electrical  Readings  of  12-inch  Machine. 


V 

.  P 

Direct 

P 

X  200 

W 

p 

200  X  4 

P.F. 

Y 

s 

Direct 

Connections 

A 

(A    X  52) 
P 

K.W. 

1.75  350 

50 

40. 

.44 

2. 

1  and  5 

18  200 

282 

1.95  390 

60 

48. 

.435 

2. 

1  and  6 

20  280 

340 

2.15  430 

80 

64. 

.436 

3. 

1  and  7 

22  360 

385 

2.4  280 

95 

76. 

.703 

3.2 

1  and  8 

14  560 

310 

1.9  380 

70 

56. 

.475 

2.4 

2  and  5 

19  760 

330 

2.2  440 

80 

64. 

.44 

2.4 

2  and  6 

22  880 

375 

2.45  490 

90 

72. 

.392 

3. 

2  and  7 

25  480 

415 

2.7  540 

112 

89.5 

.40 

3.1 

2  and  8 

28  080 

350 

2.2  440 

80 

64. 

.415 

2. 

3  and  5 

22  880 

375 

2.5  500 

90 

72. 

.384 

2. 

3  and  6 

27  000 

415 

2.9  580 

105 

84. 

.35 

1.5 

3  and  7 

30  160 

440 

3.2  640 

122 

97.5 

.346 

1.5 

3  and  8 

33  280 

360 

2.7  540 

95 

76. 

.391 

2.7 

4  and  5 

28  080 

410 

2.8  560 

110 

88. 

.384 

2.6 

4  and  6 

29  224 

440 

3.2  640 

130 

104. 

.37 

1.6 

4  and  7 

33  280 

475 

3.4  680 

142 

114. 

.354 

2.2 

4  and  8 

35  360 

*485 

3.05  610 

147 

118. 

.40 

3. 

4  and  8 

31  720 

*  This  set  of  readings  taken  with  the  plates  set  full  width  of  gap  12  inches. 


varying  connections  refer  to  the  same  numerals  (Fig. 
11)  as  marked  on  the  selector  panels.  The  last  column, 
secondary  amperes,  is  calculated  by  multiplying  the  pri- 
mary amperes  by  the  number  of  primary  turns  in  the 
12-inch  spot- welded  transformer,  which  is  52.  The  last 
set  of  readings  was  taken  with  the  steel-plate  test  piece 
shoved  back  in  the  machine  in  order  to  introduce  the  full 
reactance  and  to  ascertain  the  effect  this  would  have 
upon  the  power  factor. 

While  taking  these  readings  it  was  noted  that  the 
secondary  volts  across  the  electrodes  gradually  lowered 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  69 


as  the  welding  time  continued.  No  noticeable  change 
was  seen  in  the  primary  readings  during  this  short  period. 
Table  IV  shows  readings  taken  on  two  different  sets  of 


TABLE  IV. 
Showing  Drop  In  Secondary  Volts. 


W 

V 

(Direct) 

Connec- 

V 

A 

P 

P.F. 

tions 

p 

P 

K.W. 

0 

5 

10 

15 

20 

25 

SO 

sec. 

sec. 

sec. 

sec. 

sec. 

sec. 

sec. 

3  and  6 

370 

2.4  480 

100  80 

.45 

2.5 

2.3 

2.0 

1.5 

1.3 

1.3 

3  and  6 

370 

2.4  480 

100  80 

.45 

3.3 

2.5 

2.2 

2.0 

1.5 

1.3 

1.25 

3  and  7 

410 

2.75  550 

115  92 

.407 

3.0 

2.7 

2.0 

1.7 

1.5 

1.5 

3  and  7 

415 

2.70  540 

115  92 

.41 

3.0 

2.7 

2.0 

1.7 

1.5 

1.4 

connections  with  the  secondary  voltage  read  every 
five  seconds. 

Electrical  readings  were  taken  during  the  spot  weld- 
ing of  the  lug  attachment  on  the  20-pound-plate  test 
piece.   These  readings  are  given  in  Table  V  and  by  ref- 


TABLE  V. 

Electrical  Readings  Taken  While  Welding  Sample  Lug  Attachment. 


Connections 

V 

P 

A 

P 

W 

P 

K.W. 

P.F. 

V 

s 

A 

8 

4  and  7 

425 

3.2  640 

120 

96 

.353 

2.3 

33280 

4  and  7 

425 

3.5  700 

125 

100 

.336 

2.5 

36400 

4  and  7 

430 

3.1  620 

130 

104 

.39 

3.0 

32240 

4  and  7 

425 

3.2  640 

120 

96 

.353 

2.5 

33280 

3  and  7 

415 

2.8  560 

110 

88 

.379 

2.5 

29120 

3  and  7 

410 

2.9  580 

110 

88 

.407 

2.4 

30160 

3  and  7 

420 

2.9  580 

104 

83 

.340 

3.0 

30160 

3  and  7 

420 

2.95  590 

110 

88 

.355 

3.2 

30680 

erence  to  the  same  connections  shown  in  Table  III  the 
constancy  of  the  electrical  conditions  may  be  judged. 
Ten  samples  of  this  type  were  spot  welded  and  tested  for 
tensile  in  the  Olsen  testing  machine.    Table  VI  gives 


70 


SPOT  AND  ARC  WELDING 


the  results  of  this  test  and  Table  VII  gives  the  compa- 
rable results  for  the  riveted  sample.  Fig.  20  illustrates 
this  comparison  and  shows  compositely  the  general  re- 

TABLE  VI. 
Tensile  Test  of  Lug  Attachment, 
spot  welded.. 
(Electrode  pressure  15,000.    Time  on  spots  10  seconds.) 


Sample 
No. 

Open-circuit 
Voltage 

Ultimate  Load 
Pounds 

Remarks 

1-1 

455 

98,000 

Sample  forced  out  of  machine 

1-2 

455 

105,700 

Angle  bent  away  from  plate  .176" 

1-3 

455 

92,000 

4  spots  broke 

1-4 

455 

89,000 

Sample  forced  from  machine 

1-5 

407 

89,000 

All  spots  sheared 

1-6 

407 

99,300 

Sample  forced  from  machine 

1-7 

407 

67,000 

Spots  1  and  2  tore  away 

1-8 

407 

63,700 

Sample  forced  from  machine 

1-9 

455 

68,500 

1-10 

455 

73,900 

suits  of  the  tests.  On  the  left  is  the  riveted  sample  which 
invariably  sheared  three  or  all  of  its  rivets  under  an  ulti- 
mate tensile  of  45,000  to  48,000  pounds.   In  the  middle 


TABLE  VII. 

Tensile  Test  of  Lug  Attachment. 


RIVETED. 


Sample  No. 

Ultimate  Load 

Remarks 

2-1 

48,000 

Sheared  all  4  rivets 

2-2 

47,400 

Sheared  all  4  rivets 

2-3 

46,700 

Sheared  3  rivets 

2-4 

47,200 

2-5 

49,700 

Sheared  3  rivets 

2-6 

44,000 

Sheared  3  rivets 

is  the  spot-welded  sample  which  would  spring  from 
under  the  jaws  of  the  testing  machine  after  an  ultimate 
load  of  89,000  to  100,000  pounds.  To  the  left  an  attempt 
was  made  photographically  to  show  the  twisting  of  the 


DEMONSTRAITON  OF  HEAVY  SPOT  WELDING  71 


20-pound  plate  which  caused  the  sample  to  spring  from 
the  jaws  of  the  testing  machine.  It  will  be  noticed  in 
Table  VI  that  the  last  four  samples  tested  at  an  ulti- 


I 


Fig.  20. — Comparison  of  riveted  and  spot- welded  test  piece. 


mate  load  of  63,700  to  73,900  pounds.  It  will  also  be 
seen  in  Table  V  that  the  connections  were  changed  for 
these  four  samples.  This  was  done  after  the  first 
samples  were  pulled  in  order  that  tests  might  be  made 


72 


SPOT  AND  ARC  WELDING 


that  would  shear  the  lug  attachments  in  order  to  enable 
a  view  of  the  spot  weld.  The  results  showed  that  a  good 
weld  could  be  made  at  reduced  amperage. 

The  riveted  test  pieces  of  the  cross-connection  sample 
were  next  prepared  for  tensile  test.  Before  this  could 
be  done  small  pads  of  3/2 -inch  plate  were  arc  welded  to 
the  small  sides  of  the  sample  (see  Fig.  21) .   These  pads 


Fig.  21. — Comparison  of  riveted  and  combination  arc-  and  spot- welded  sample. 


were  about  3^  inches  wide  and  were  found  necessary  in 
order  to  obtain  a  satisfactory  pull  in  the  testing  machine. 
These  test  pieces  were  too  heavy  for  the  testing  machine, 
which  though  originally  rated  at  150,000  pounds  capac- 
ity, was  only  safe  to  operate  up  to  124,000  pounds.  At 
this  ultimate  load  the  ten  ^-inch  rivets  were  either 
sheared  entirely,  or  the  angle  broke,  or  the  rivets 
stretched.  The  spot-welded  samples  were  in  excess  of 
the  capacity  of  the  12-inch  spot  welder  for  welding  three 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  73 


thicknesses.  A  number  of  samples  were  made  and 
pulled  with  interesting  results  as  far  as  examination  of 
the  condition  of  the  spot  welds  after  shearing  strains. 
Later  the  angles  were  reduced  to  i^-inch  thickness,  but 
when  this  change  was  made  the  uniformity  tests  were 
in  progress  and  it  was  not  considered  of  value  to  con- 
tinue this  comparison.  In  view  of  the  original  intention 
which  was  the  relative  value  of  mechanical  caulking 
versus  electric  welding,  a  sample  was  made  both  spot 
welded  and  arc  welded.  That  is,  the  edges  of  the  angles 
were  arc  welded.  This  test  piece  was  set  up  in  the  test- 
ing machine  and  resulted  in  breaking  the  head  of  the 
machine.  The  strain  on  the  sample  in  both  a  static  and 
dynamic  sense  must  have  been  very  great.  This  special 
sample  is  shown  on  the  left  in  Fig.  21  after  the  test  had 
been  made.  There  were  no  signs  of  distress  in  any  of 
the  joints.  It  has  been  sent  to  the  Commercial  Museum, 
Philadelphia,  Pa.,  where  it  may  be  seen  by  any  one  in- 
terested. On  the  right  in  this  same  illustration  is  one  of 
the  riveted  samples  in  which  the  ^-inch  angle  broke  in 
line  of  the  rivets  at  an  ultimate  load  of  118,900  pounds. 

The  results  of  the  first  trial  for  uniform  strength  of 
spot  welds  in  one  long  seam  was  not  successful.  It 
brought  to  light  the  necessity  of  two  important  points 
in  the  preparation  of  the  steel  plates  and  f  ocussed  atten- 
tion on  the  serious  problem  of  the  electrode  tips.  Dur- 
ing the  first  test  no  care  was  given  as  to  the  condition  of 
the  material.  It  was  spot  welded  as  received.  If  it  hap- 
pened to  be  clean  on  the  surfaces  next  to  the  electrode 
tips  these  tips  were  still  used;  if,  on  the  other  hand,  much 
scale  and  rust  rested  on  these  surfaces  the  tips  were 
badly  burned  with  the  result  that  they  had  to  be  renewed. 


74 


SPOT  AND  ARC  WELDING 


This  was  one  of  the  reasons  why  the  27-ineh  machine  was 
now  used.  The  builders  had  changed  the  method  of  re- 
newing the  tips  which  reduced  the  time  and  inconveni- 
ence very  considerably.    In  like  manner  in  the  early 

TABLE  vni. 


Glasgow  Iron  Works,  Pottstown. 
Feb.  24,  1919. 


No. 

Load  Lbs. 

Time  Sec. 

Remarks 

Electrode 
Changed 

I 

49,700 

15 

2 

41,600 

12 

3 

40,600 

12 

No.  3  (b) 

4 

41,100 

12 

5 

41,300 

12 

Q 

43,700 

12 

< 

7 

46,100 

12 

No  2  Cb) 

8 

45,200 

12 

9 
10 

51,200 
35  QOO 

12 
12 

No.  1  (c) 

11 

41,700 

12 

< 

12 

40,700 

12 

13 

44^200 

12 

No.  2  (a) 

14 

43,800 

12 

15 

44,500 

12 

16 

41,200 

12 

< 

17 

31,300 

12 

No.  1  (b) 

18 

43,700 

12 

19 

39,400 

12 

< 

20 
21 

40,800 
43,400 

12 
12 

No.  1  (a) 

22 

41,900 

12 

23 

40,300 

12 

24 

46,800 

12 

No.  2  (c) 

25 

42,600 

12 

*  Re-Spotted 

*26 

43,700 

12 

Full  time  after  26 

27 

42,100 

12 

28 

41,600 

12 

Fore  plate 

No.  3  (a) 

29 

44,000 

12 

30 

48,800 

15 

Pulled  spot  out 

10'— 10"  Plate  20  lbs.— if"— 2 lap— Green  operator— 27"  G.  E.  Spot  Welder. 
Present  at  test:  Green,  Schrader  and  Hornor. 
Average  break,  42,750  lbs. 

Shearing  stress  (single  shear)  steel  rivets  and  steel  plates: 

Half -inch,  12,250  lbs. 

Three-quarter  inch,  25,600  lbs. 

Seven-eighths,  34,100  lbs. 

One  inch,  43,700  lbs. 
Rusted,  scale. 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  75 


tests  no  attention  was  paid  to  the  surfaces  of  the  mate- 
rials between  the  lapped  portions.  A  few  tests  indicated 
clearly  that  the  reverse  condition  was  more  desirable  for 
welding,  namely,  that  the  surfaces  between  the  plates  to 
be  joined  be  dirty,  i.e.,  have  some  mill  scale  or  rust.  This 
does  not  mean  that  clean  surfaces  cannot  be  welded,  but 
that  more  successful  and  uniform  welds  are  made  in 
shorter  time,  with  less  current,  and  less  pressure.  This 
fact  must  be  observed  by  those  who  wish  to  repeat  the 
results  here  shown. 

The  results  of  the  second  set  of  spots  made  for  the 
uniformity  tests  are  given  in  Table  VIII.  These  spots 
were  not  made  consecutively,  as  it  was  thought  at  the 
time  that  the  sequence  of  welds  might  bear  some  relation 
to  the  results.  This  consideration  was  not  borne  out  by 
subsequent  tests.  So  that  the  following  samples  were 
all  made  consecutively.  The  test  pieces  were  all  of  the 
same  nature:  Two  10-foot  lengths  of  a  desired  thickness 
of  plate;  these  two  pieces  lapped  about  2^  inches  to  2% 
inches,  arc  welded  at  intervals  along  the  edge,  and  then 
spot  welded  from  one  end  to  the  other.  The  first  sample 
was  unfortunately  cut  in  a  shearing  press  which  so  de- 
formed the  samples  that  they  were  awkward  to  place  in 
the  testing  machine.  The  surfaces  next  to  the  electrode 
tips  for  all  samples  were  cleaned  by  a  portable  grinder 
in  way  of  the  spots  before  welding.  Although  no  par- 
ticular insistence  was  needed,  the  plates  were  placed  so 
that  the  surfaces  between  had  the  ordinary  mill  scale 
and  rust  usual  in  practice.  It  could  be  easily  noted  when 
pulling  the  samples  which  were  the  relatively  clean  por- 
tions of  the  plates. 

A  series  of  tests  were  now  made  using 


76 


SPOT  AND  ARC  WELDING 


and  ^-inch  steel  plates,  including  electrical  readings  for 
each  spot  made.  The  results  are  given  in  Tables  IX,  X, 
XI,  and  XII.  It  will  be  seen  with  what  constancy  the 
electrical  conditions  were  maintained  and  how  little  they 
affected  the  results.   After  these  particular  tests  no  elec- 


TABLE  IX. 

Uniformity  Test  3^-inch  Steel. 
Test:  10-foot  }i"  S.  Plate 
27"  G.  E.  Spot  Welder 
Pressure:  18,750  lbs.  at  electrodes 
Voltage:  325.    Amperes:  22,230 
Time  of  each  spot:  12  seconds 


No.  of  Spot 


Ultimate  Load 


Amperes 


Remarks 


1 

2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
20 
21 
22 
23 
24 
25 
20 
27 
28 
29 
30 


29,700 
19,000 
20,500 
20,200 
19,300 
18,900 
20,100 
20,100 
20,300 
19,400 
26,400 
19,100 
19,700 
19,000 
17,600 
19,200 
18,900 
20,200 
18,600 
17,100 
30,300 
19,900 
20,600 
20,900 
19,800 
22,700 
19,100 
19,000 
20,000 
26,000 


23,400 
22,620 
22,620 
22,230 
22,230 
22,230 
22,230 
22,230 
22,230 
22,230 
22,230 
22,230 
22,620 
22,230 
22,230 
22,230 
22,230 
22,230 
22,230 
22,230 
22,230 
22,230 
22,230 
22,230 
22,620 
22,230 
22,620 
22,620 
22,620 
23,400 


Spot  in  line  with  tack  weld 


Spot  in  line  with  tack  weld 


Spot  in  line  with  tack  weld 


Spot  in  line  with  tack  weld 


Notes.— Present  at  welding  test:  Same  as  on  Y^"  S.  P. 

Pulling  tests  made  March  18,  1919,  at  Glasgow  Iron  Works. 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  77 


trical  readings  were  taken.   As  the  and  3^ -inch 

plates  were  below  the  designed  rating  of  the  machine  the 
results  given  are  arbitrary,  as  the  current  taps  may  be 
selected  to  give  more  or  less  current  and  successful  weld- 


TABLE  X. 
Uniformity  Test  %-inch  Steel. 
March  13,  1919. 
Test:  10-foot  y^'  S.  Plate 
Ti"  G.  E.  Spot  Welder 
Pressure:  18,750  lbs.  at  electrodes 
Voltage:  395.   Amperes:  27,900 
Time  of  each  spot:  12  seconds 


No.  of  Spot 


Ultimate  Load 


Amperes 


Remarks 


1 

3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
20 
21 
22 
23 
24 
25 
26 
27 
28 
29 
30 


42,100 
27,800 
27,300 
30,900 
29,100 
30,100 
32,000 
30,500 
32,600 
33,000 
39,900 
27,600 
30,000 
30,400 
30,100 
32,200 
36,100 
31,600 
30,300 
34,100 
31,000 
25,700 
26,500 
29,100 
29,200 
29,300 
31,100 
30,800 
30,900 
28,000 


28,470 
27,690 
28,080 
27,690 
27,690 
27,690 
27,300 
26,910 
27,300 
26,910 
27,300 
27,456 
27,456 
27,534 
27,300 
27,300 
27,300 
27,690 
27,690 
27,690 
27,690 
27,300 
27,690 
27,300 
27,300 
26,910 
27,300 
27,300 
27,610 
28,470 


Spot  pulled  out 


Spot  pulled  out 
Spot  pulled  out 


Spot  in  line  with  tack  weld 


Spot  in  line  with  tack  weld 


Notes. — Present  at  welding  test:  Seltzer  and  Newell  (Steamboat  Inspection  Service),  Martin  (Ameri- 
can Bureau  of  Shipping),  Stewart  and  Homor. 
Pulling  tests  made  March  18,  1919,  Glasgow  Iron  Works. 


78 


SPOT  AND  ARC  WELDING 


ing  accomplished  by  a  relative  adjustment  of  the  time  of 
making  the  weld.  This  brought  these  sizes  into  the  realm 
of  shop-production  questions  with  which  this  demonstra- 
tion had  nothing  to  do. 

TABLE  XI. 
Uniformity  Test  3^-inch  Steel. 
March  12,  1919. 
Test:  10-foot       S.  Plate 
27"  G.  E.  Spot  Welder 
Pressure:  18,750  lbs.  at  electrode 
Taps  set  constant  4-8 
Voltage:  440.   Amperes:  31,200 
Time  of  each  spot:  13  seconds 


No.  of  Spot 

Ultimate  liOad 

Amperes 

Remarks 

1 

44,100 



32,370 

Spot  in  line  with  tack  weld 

2 

42,000 

31,200 

3 

38,000 

31,200 

4 

33,500 

31,200 

5 

28,900 

31,200 

6 

34,000 

31,200 

7 

35,000 

30,810 

8 

44,000 

31,200 

9 

38,500 

31,200 

10 

34,100 

30,810 

11 

29,000 

30,810 

12 

30,700 

31,590 

13 

35,300 

31,200 

14 

38,000 

30,810 

15 

32,600 

30,810 

16 

28,800 

31,590 

17 

27,600 

31,590 

18 

49,200 

30,810 

Spot  in  line  with  tack  weld 

19 

36,500 

31,200 

20 

40,700 

31,200 

21 

38,000 

31,590 

•22 

33,800 

31,200 

23 

31,600 

31,200 

24 

23,900 

31,200 

25 

30,200 

31,590 

26 

30,400 

30,810 

27 

30,200 

31,590 

28 

51,200 

32,370 

Spot  in  line  with  tack  weld 

Notes. — Present  at  test:  J.  B.  Stewart,  H.  A.  Hornor. 
Clean  steel. 

Pulling  tests  made  March  18,  1919,  Glasgow  Iron  Works. 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  79 


It  will  be  seen  that  the  time  given  the  ^-inch  samples 
was  13  seconds  (Table  XI).  It  was  expected  that 
better  results  would  be  attained  by  increasing  the  time, 
so  a  smaller  sample  (5  feet  in  length)  was  run  through 

TABLE  XII. 
Uniformity  Test  ^-inch  Steel. 
March  13,  1919. 

Test:  10-foot      S.  Plate 
n"  G.  E.  Spot  Welder 


Pressure:  18,750  lbs.  at  electrodes 
Voltage:  440.   Amperes:  31,200 
Time  of  each  spot  constant:  18  seconds 


No.  of  Spot 

Ultimate  Load 

Amperes 

Remarks 

1 

51,200 

32,370 

31,590 

Sample  held  for  other  tests 

3 

29,500 

31,980 

4 

19,700 

32,370 

5 

32,370 

Sample  held  for  other  tests 

6 

28,600 

31,980 

7 

26,700 

31,980 

8 

22,200 

32,370 

9 

15,000 

32,370 

10 

18,600 

31,980 

Spot  in  line  with  tack  weld 

11 

23,200 

32,370 

12 

38,300 

32,370 

13 

24,600 

32,214 

14 

26,600 

32,370 

15 

31,100 

32,370 

16 

33,400 

32,214 

17 

31,000 

32,136 

18 

29,100 

32,370 

19 

20,900 

32,370 

20 

44,100 

31,590 

Spot  in  line  with  tack  weld 

21 

35,700 

31,590 

22 

32,800 

31,200 

23 

27,900 

31,590 

24 

30,000 

31,200 

25 

35,800 

31,200 

26 

31,300 

31,200 

27 

29,600 

31,590 

28 

21,200 

31,200 

29 

35,700 

31,595 

30 

49,900 

32,370 

Notes. — Present  at  welding  tests:  J.  B.  Stewart,  Seltzer  (Steamboat  Inspection  Service),  Newell 
(same),  H.  A.  Hornor. 
Pulling  tests  made  March  18,  1919,  Glasgow  Iron  Works. 


80 


SPOT  AND  ARC  WELDING 


test  without  electrical  readings  at  15  seconds  with  results 
as  shown  in  Table  XIII.  The  ^-inch  sample  (Table 
XII)  was  welded  with  a  constant  time  of  18  seconds  for 
each  spot,  and  as  this  was  the  maximum  capacity  of  this 
machine  better  results  could  only  be  obtained  by  increas- 
ing the  time.  Table  XIV  gives  the  results  on  a  5-foot 
sample  with  spot  welds  made  in  25  seconds,  all  the  other 
conditions  remaining  the  same. 

These  results  were  laid  before  the  technicians  of 
Lloyd's  Register  of  Shipping,  the  American  Bureau  of 
Shipping,  and  the  U.  S.  Steamboat  Inspection  Service 
of  the  Bureau  of  Commerce.  It  was  then  suggested 
that  a  similar  series  of  tests  be  made  as  a  check  upon 
what  had  been  done  and  with  variations  in  the  time  of 
making  the  spots  in  each  sample.  Electrical  readings 
were  not  required  for  each  spot,  but  readings  of  the 
circuit  were  taken  from  time  to  time  to  assure  that  they 
were  holding  to  a  constancy  that  would  not  disturb  the 
results.  The  records  of  these  tests  are  given  in  Tables 
XV,  XVI,  XVII,  and  XVIII.  The  first  ten  spots  of 
the  J4"i^ch  sample  were  given  16  seconds  each,  the  next 
ten  spots  were  given  12  seconds  each,  and  the  last  ten 
spots  8  seconds  each.  The  average  ultimate  load  in 
pounds  for  the  first  ten  spots  was  16,720  pounds,  for  the 
next  ten  spots  it  was  17,540  pounds,  and  for  the  last 
series  17,560  pounds.  The  first  ten  spots  of  the  ^-inch 
sample  were  given  each  16  seconds,  with  an  average  ulti- 
mate load  of  34,720  pounds,  the  next  ten  spots  were 
given  12  seconds  each,  with  an  average  ultimate  load  of 
32,790  pounds,  and  the  last  ten  spots  were  given  8  sec- 
onds each,  with  an  average  ultimate  load  of  27,770 
pounds.   The  first  ten  spots  of  the  i/^-inch  sample  were 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING 


TABLE  XIII. 
Uniformity  Test  %-inch  Steel. 
Test:  5-foot       S.  Plate 
Pressure:  18,750  lbs.  at  electrodes 
Voltage:  440.   Amperes:  31,200 
Time  of  each  spot:  15  seconds 


No.  Spot 

Ultimate  Load 

Remarks 

1 

50,000 

Spot  pulled  out 

2 

Sample  held  for  other  tests 

3 

40,000 

4 

41,800 

5 
6 

41,900 
43,000 

7 

Sample  held  for  other  tests 

8 

38,100 

9 

35,000 

10 

38,600 

11 

Sample  held  for  other  tests 

12 

35,100 

13 

37,700 

14 

Sample  held  for  other  tests 

15 

45,400 

Welding  done  March  19,  1919. 

Pulling  tests,  March  ^20,  1919,  Pottstown,  Pa. 


TABLE  XIV. 

Uniformity  Test  -^s-inch  Steel. 
Test:  5-foot  %"  S.  Plate 
Pressure:  18,750  lbs.  at  electrode 
Voltage:  440.   Amperes:  31,200 
Time  of  each  spot:  25  seconds 


No.  Spot 

Ultimate  Load 

1 

Sample 

2 

52,100 

Spot  in 

3 

47,500 

4 

Sample 

5 

49,200 

6 

49,400 

7 

64,700 

8 

Sample 

9 

52,600 

10 

54,200 

11 

Sample 

12 

53,700 

13 

52,900 

14 

50,900 

15 

60,300 

Remarks 


Average,  53,409  lbs. 
6 


82 


SPOT  AND  ARC  WELDING 


TABLE  XV. 
Lloyd's  Tests: 
10'— 1^"  S.  P.  Tensile  Test. 
March  27,  1919. 
Glasgow  Iron  Works,  Pottstown,  Pa. 

Pressure  at  electrode  constant:  18,750  lbs. 
Amperes:  22,230.   Volts:  325 


No. 

Time 

Diameter 

Ultimate 

Remarks 

Spot 

Sec. 

Spot,  Inches 

Load,  Lbs. 

1 

lo 

74 

z\)j  OUU 

1  fl 
10 

74 

iy,uuu 

D  n  J 

X  ullecl  out  spot 

6 

10 

3y 
74 

iy,ouu 

Gas  hole 

A 

4 

10 

74 

lo,  /UU 

5 

10 

13/ 
716 

1  >7fifi 

10,  /  uu 

Iwo  small  gas  holes 

a 
O 

10 

74 

lDfD\J\J 

7 

1  ft 
10 

11/  " 
/16 

10,  lUU 

a      11         u  1 
bmall  gas  hole 

8 

1  fi 
lo 

11/ 
716 

1  Q  /I  AA 
lo,4!UU 

Small  gas  hole 

n 

y 

10 

11/ 
716 

1  O  OAA 
1  *UU 

Small  gas  hole 

lU 

1  fi 
10 

11/  'f 
716 

1  fi  OAA 
10,  %UU 

11 

1% 

11/  " 
716 

1  >y  AAA 

1  /  ,yuu 

C        11            U    1     /TM    4-          IJ  IJ 

hmall  gas  hole  (i  late  cold — weld- 
ing resumed) 

1% 

1  o 

11/ 
716 

1  fi  AAA 
10,UUU 

13 

1% 

11/  " 
/16 

1  Q  CAA 
lOjOUU 

a      11         I,  1 
bmall  gas  hole 

14 

12 

16,700 

Small  gas  hole 

lo 

/16 

lO,  <uu 

Small  gas  hole 

16 

12 

18,000 

Small  gas  hole 

17 

L% 

11  " 

/16 

1  Q  AAA 

lo,UUU 

18 

12 

'Ke" 

16,900 

Small  gas  hole 

19 

12 

•Ke" 

18,100 

Small  gas  hole 

20 

12 

'Ks" 

18,600 

Small  gas  hole 

21 

8 

17,200 

22 

8 

16,700 

23 

8 

57^' 
78 

17,300 

Small  gas  hole 

24 

8 

16,600 

Small  gas  hole 

25 

8 

16,100 

Small  gas  hole 

26 

8 

15,200 

Small  gas  hole 

27 

8 

16,800 

Small  gas  hole 

28 

8 

%" 

18,200 

Small  gas  hole 

29 

8 

%" 

21,800 

Small  gas  hole.  Rusted  specimen; 
slag  between  plates 

30 

8 

'K6" 

19,700 

Present  at  test:  Same  as  test. 

Tests  show  a  torsional  strain  on  samples  while  in  machine. 
Average  load  first  ten  at  sixteen  seconds,  16,720. 
Average  load  second  ten  at  twelve  seconds,  17,540. 
Average  load  third  ten  at  eight  seconds,  17,560. 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  83 


TABLE  XVI. 
Lloyd's  Tests. 

S.  P.  Tensile  Test. 
March  27,  1919. 
Glasgow  Iron  Works,  Pottstown,  Pa. 

Pressure  at  electrodes  constant:  18,750  lbs. 
Amperes:  27,700.   Volts:  395 


No. 

Time 

Diameter 

Ultimate 

Remariks 

Spot 

Seconds 

Spot,  Inches 

Load,  Lbs, 

1 

16 

34,700 

Spot  pulled  out 

2 

16 

31,100 

Small  gas  hole 

3 

16 

34,900 

Small  gas  hole 

4 

16 

36,900 

Small  gas  hole 

5 

16 

v 

34,500 

Small  gas  hole.    Spot  started  to 
pull  out 

6 

16 

Vi" 

35,600 

Small  gas  hole 

7 

16 

1" 

34,300 

Small  gas  hole 

8 

16 

v 

34,100 

Small  gas  hole 

9 

16 

34,800 

Spot  pulled  out 

10 

16 

37,300 

Highly  rusty  material 

11 

12 

31,700 

Small  gas  hole 

12 

12 

28,800 

Small  gas  hole 

13 

12 

\" 

32,200 

Small  gas  hole 

14 

12 

\" 

34,400 

Small  gas  hole 

15 

12 

\" 

36,200 

Small  gas  hole.  Fracture  around 

edge  of  spot 

16 

12 

\" 

33,800 

Small  gas  hole 

17 

12 

30,500 

Small  gas  hole 

18 

12 

32,300 

Small  gas  hole 
Small  gas  hole 

19 

12 

34,800 

20 

12 

33,200 

Small  gas  hole 

21 

8 

25,400 

Small  gas  hole 

22 

8 

28,700 

Small  gas  hole 

23 

8 

25,500 

Small  gas  hole 

24 

8 

28,600 

Small  gas  hole 

25 

8 

26,600 

Small  gas  hole 

26 

8 

24,600 

Small  gas  hole 

27 

8 

%" 

22,000 

Small  gas  hole 

28 

8 

29,900 

Small  gas  hole 

29 

8 

%" 

29,800 

Small  gas  hole 

30 

8 

36,600 

Small  gas  hole  (Very  slight) 

Present  at  test:  Same  as  test. 

Tests  show  a  torsional  strain  on  samples  while  in  machine. 
Plate  bent  before  spot  pulled. 
Average  load  first  ten  at  sixteen  seconds,  34,720. 
Average  load  second  ten  at  twelve  seconds,  32,790. 
Average  load  third  ten  at  eight  seconds,  27,770. 


84 


SPOT  AND  ARC  WELDING 


TABLE  XVII. 

Lloyd's  Tests. 
10—3^''  S.  P.  Tensile  Test. 
March  27,  1919. 
Glasgow  Iron  Works,  Pottstown,  Pa. 

Pressure  at  electrodes  constant:  18,750  lbs. 
Amperes:  31,200.   Volts:  440. 


No. 

Time 

Diameter 

Ultimate 

Remarks 

Spot 

Seconds 

Spot.  Inches 

Load,  Lbs. 

1 

20 

41,000 

End  spot.          wide  plate.  Plate  fractured 

20 

1" 

41,900 

Started  to  tear  around  rim  of  spot 

3 

20 

iKe" 

42,800 

4 

20 

1%" 

41,100 

Spot  pulled  out  V  diameter 

5 

20 

iKe" 

39,100 

Plate  fracturing  in  direction  of  grain.  Spot 
pulling  out 

6 

20 

IKs" 

43,100 

Spot  pulled  out 

7 

20 

IKe" 

41,400 

Plate  fracturing  in  direction  (l^'O  of  grain. 
Spot  pulling  out 

8 

20 

1" 

40,700 

Plate  fracturing  in  direction          of  grain. 
Spot  pulling  out 

9 

20 

i%" 

41,600 

Plate  fracturing  in  direction  (l^g'O  of  grain. 
Spot  pulling  out 

10 

20 

38,100 

Plate  fracturing  in  direction  (1%'0  oi  grain. 
Spot  pulling  out 

11 

15 

1" 

39,000 

Slight  plate  fracture      around  edge  of  spot. 

12 

15 

IKe" 

39,900 

Plate  fractured.   Spot  pulled  out 

13 

15 

1" 

36,300 

Fractured  around  edge  of  spot 

14 

15 

iW 
1" 

43,000 

Heavy  fracture  around  edge  of  spot 

15 

15 

39,300 

Slight  fracture  around  edge  of  spot 

16 

15 

1" 

43,900 

Slight  fracture  around  edge  of  spot 

17 

15 

1" 

43,700 

Heavy  fracture  around  edge  of  spot.  Spot 
pulling  out 

18 

15 

iKe" 

41,600 

Slight  fracture  around  edge  of  spot 

19 

15 

1" 

41,800 

Slight  fracture  around  edge  of  spot 

20 

15 

IM" 

50,200 

Heavy  fracture  around  edge  of  spot.  Spot 
pulling  out 

21 

10 

%" 

33,500 

22 

10 

31,200 

23 

10 

24,300 

24 

10 

%" 

34,000 

25 

10 

33,100 

26 

10 

7/// 

/8 

33,900 

27 

10 

%" 

33,000 

28 

10 

35,500 

29 

10 

35,400 

30 

10 

44,900* 

Fractured  around  edge  of  spot 

•  Plate  bent  before  spot  pulled. 

Tests  show  a  torsional  strain  on  samples  while  in  machine. 
Average  load  first  ten  at  twenty  seconds,  41,080. 
Average  load  second  ten  at  fifteen  seconds,  41,780. 
Average  load  third  ten  at  ten  seconds,  34,180. 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  85 


TABLE  XVIII. 
Lloyd's  Tests. 
10'—%''  S.  P.  Tensile  Test. 
March  27,  1919. 
Glasgow  Iron  Works,  Pottstown,  Pa. 

Pressure  at  electrodes  constant:  18,750  lbs. 
Amperes:  31,200. j Volts:  440 


No. 

Time 

Diameter 

Ultimate 

Renjarks 

Spot 

Seconds 

spot,  Inches 

Load,  Lbs. 

1 
1 

59  500 

9 

A/16 
A  716 

fiOO 

o 

25 

K'X  700 

£D 

f^/L  700 

K 
O 

25 

1" 

44  QOO 

(i 

o 

25 

1" 

42  100 

'7 
# 

1" 

800 

Q 
o 

25 

1" 

44  100 

Q 

25 

A  716 

4^=1  'lOO 

in 

.  AO 

1" 

4^  fiOO 

11 

20 

716 

Qfi  QOO 

20 

1/16 

4Q  900 

lo 

/16 

^«  ^00 

14 

20 

1" 

34,300 

ID 

zo 

1 

QQ  QOO 

16 

20 

1" 

33,200 

17 
1  / 

1" 

41  100 

18 

20 

'Ym" 

32' 600 

19 

20 

%" 

26,700 

20 

20 

%" 

26,900 

21 

15 

'Yn' 

32,300 

22 

15 

29,900 

23 

15 

Wu' 

24,000 

Gas  hole  in  spot 

24 

15 

28,700 

25 

15 

21,200 

26 

15 

29,900 

27 

15 

%" 

18,000 

28 

15 

'Yu" 

33,500 

29 

15 

30,700 

Regular  spot  adjacent  to  arc- weld 
tack 

30 

15 

29,400 

Present  at  test:  Messrs.  Aspinall,  Frickey  (A.I.S.C.),  J.  B.  Stewart,  M.  I.  Eshbock,  H.  A.  Hornor. 
The  tests  show  a  torsional  strain  on  samples  while  in  machine. 
Average  load  first  ten  at  twenty-five  seconds,  48,740. 
Average  load  second  ten  at  twenty  seconds,  36,310. 
Average  load  third  ten  at  fifteen  seconds,  27,760. 


86 


SPOT  AND  ARC  WELDING 


given  20  seconds  each,  with  an  average  ultimate  load  of 
41,080  pounds,  the  next  ten  spots  were  given  15  seconds 
each,  with  an  average  ultimate  load  of  41,780  pounds, 
and  the  last  ten  spots  were  given  ten  seconds  each  of  an 
average  ultimate  load  of  34,180  pounds.  The  first  ten 
spots  of  the  ^-inch  sample  were  given  25  seconds  each, 
with  an  average  ultimate  load  of  48,740  pounds,  the 
next  ten  spots  were  given  20  seconds  each,  with  an  aver- 
age ultimate  load  of  36,310  pounds,  and  the  last  ten 
spots  were  given  15  seconds  each  with  an  average  ulti- 
mate load  of  27,760  pounds. 

Table  XIX  gives  the  results  of  pulling  tests  of  a 
5-foot  sample  of  ^-inch  plate  spot  welded  with  the 
duplex  machine.  All  the  spots  were  made  in  pairs  except 

TABLE  xix. 
Tensile  Test        S.  P. 
April  11,  1919. 
Glasgow  Iron  Works,  Pottstown,  Pa. 
Welding  done  on  6-ft.  Duplex  Machine 


No.  Spot 

Ultimate  Load 

Remarks 

16 

66,700 

17 

81,100 

Single  spot 

18 

66,800 

19 

61,900 

Broke  plate 

20 

54,400 

21 

72,300 

Broke  plate 

22 

61,000 

23 

64,100 

Broke  plate 

24 

43,300 

25 

70,300 

26 

47,800 

27 

64,500 

28 

45,400 

29 

61,400 

Average,  61,500. 
Sheer  1"  rivet,  43,700. 

Present  at  welding:  Stewart  and  Hornor,  April  9,  1919. 
Present  at  pulling:  Stewart  and  Eshbock,  April  11,  1919. 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  87 


Number  17,  which,  as  indicated,  was  made  with  a  single 
pair  of  electrodes  in  40  seconds.  It  required  eight  opera- 
tions to  complete  this  sample  and  the  spots  were  made 
under  a  pressure  at  each  electrode  of  approximately 
22,500  pounds  in  the  following  time  intervals:  30  and  28 
in  fifty  seconds;  26  and  24  in  fifty-three  seconds;  22  and 
20  in  fifty-five  seconds;  18  and  16  in  fifty-five  seconds; 
29  and  27  in  fifty-four  seconds;  25  and  23  in  sixty-five 
seconds;  21  and  19  in  sixty-five  seconds.  This  sample 
was  very  bulky,  difficult  with  rigging  at  hand  to  hold  in 
the  spot  welder,  and,  in  addition,  the  arc-weld  tacking 
repeatedly  failed  to  hold  the  plates  together.  For  these 
reasons  spot  No.  30  being  the  end  spot  did  not  give  good 
results.  The  other  spots  upon  examination  were  excel- 
lent, and  there  was  no  doubt  that  this  performance  could 
be  repeated  indefinitely  with  as  good  or  better  results. 
Electrical  readings  were  taken  for  each  of  the  eight 
operations;  the  calculated  secondary  current  averaged 
35,520  amperes,  the  open  voltage  averaged  481,  and  the 
closed  voltage  averaged  369.  The  average  voltage  drop 
was  112  volts.  This  was  an  excessive  amount,  but  all 
the  available  materials  had  been  exhausted  for  reducing 
this  drop  which  initially  was  over  150  volts.  The  results 
under  this  limitation  proved  that  the  apparatus  when 
supplied  with  the  correct  voltage  and  current  would 
more  than  meet  the  specified  requirements.  Also  that 
the  element  of  time  in  making  the  spots  under  given  con- 
ditions is  a  relative  question  involving  other  elements 
than  the  electrical  characteristics  and  appertain  to  shop- 
production  methods. 

The  results  of  the  final  tests  made  are  given  in 
Table  XX  and  show  the  tensile  strength  of  two  and 


88 


SPOT  AND  ARC  WELDING 


three  spots  in  a  row.  Samples  were  made  up  of  ^^-inch 
steel  plate  and  spot  welded  in  the  same  manner  as  the 
other  samples.  After  spot  welding  they  were  cut  in 
strips  and  pulled  for  ultimate  tensile.  The  entire  series 
is  not  shown.  The  purpose  of  this  test  was  to  investigate 
and  compare  the  lapping  of  the  plates  as  in  a  single-, 
double-,  treble-,  and  quadruple-riveted  joint.  The 
single-spot  samples  were  lapped  3  inches  and  the  results 
were  similar  to  those  already  given.  The  double-spot 
sample  was  lapped  6  inches  with  results  as  shown  in 
Table  XX.   The  treble-spot  sample  was  lapped  9  inches 

TABLE  XX. 
Tensile  Test. 
April  10  and  11,  1919. 
Glasgow  Ieon  Works,  Pottstown,  Pa. 
2  Spots  in  Y^'  S.  P. 


No.  Spot 

Ultimate  Load 

Remarks 

1 

85,800 

Pulled  April  10,  1919 

2 

66,200 

Pulled  April  10,  1919 

3 

77,700 

Pulled  April  11,  1919 

4 

74,100 

Pulled  April  11,  1919 

5 

85,100 

Pulled  April  11,  1919 

6 

83,400 

Pulled  April  10,  1919 

Tensile  Test. 
3  Spots  in  yq'  S.  P. 


No.  Spdt 

Ultimate  Load 

Remarks 

1 

115,800 

Pulled  April  10,  1919 

■  2 

92,200 

Pulled  April  10,  1919 

3 

89,900 

Pulled  April  11,  1919 

4 

85,200 

Pulled  April  11,  1919 

5 

97,000 

Pulled  April  11,  1919 

6 

124,500 

Pulled  April  10,  1919 

Limit  of  testing  machine 

(sample  not  affected) 

Present  at  welding:  Stewart  and  Hornor. 

Present  at  pulling  April  10, 1919:  Messrs.  Higgins,  Stewart,  Eshbock, 

Hornor,  Smith,  Ker. 
Present  at  pulling  April  11,  1919:  Eshbock  and  Stewart. 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  89 


with  results  as  given  in  the  same  table.  The  quadruple- 
spot  sample  was  lapped  12  inches.  This  is  the  standard 
lapping  "  in  each  case  for  a  ship's  riveted  joints.  The 
quadruple-spot  sample  either  exceeded  the  pulling 
capacity  of  the  testing  machine,  so  that  no  results  were 
possible,  or  the  original  plate  material  would  break  some 
distance  from  the  welded  joint,  usually  about  4  to  6 
inches  from  the  last  spot.  These  investigations  lead  to 
the  conclusion  that  much  material  can  be  saved  in  steel 
ship  construction  when  designs  are  based  on  the  spot- 
welding  method. 

What  do  these  results  mean  in  a  broad  view  of  the 
joining  of  heavy  steel  members?  The  answer  is  clear. 
Those  who  are  familiar  with  ship  designs  know  the  con- 
servative requirements  placed  upon  the  strength  of 
joints  and  strength  of  materials  for  the  vital  parts  of  the 
hull  structure.  It  would  seem  logical  that  any  method 
of  joining  that  would  meet  or  exceed  the  specifications 
of  Lloyd's  Register  could  be  employed  in  other  applica- 
tions. Compare  Lloyd's  Requirements  with  the  results 
given  above.  For  thicknesses  of  steel  plate  0.22  and 
under,  ^-inch  steel  rivets  are  required;  for  thicknesses 
of  0.22  and  not  exceeding  0.34,  ^-inch  rivets;  for  thick- 
nesses of  0.34  and  not  exceeding  0.48,  %-inch  rivets;  for 
thicknesses  of  0.48  and  not  exceeding  0.66,  J^-inch 
rivets;  for  thicknesses  of  0.66  to  0.88,  1-inch  rivets.  The 
single-shearing  stress  of  rivets  of  the  sizes  mentioned  are : 

%  inch  steel  rivet   12,250  pounds 

%  inch  steel  rivet    18,300  pounds 

%  inch  steel  rivet   25,600  pounds 

%  inch  steel  rivet    34,100  pounds 

1    inch  steel  rivet    43,700  pounds 


90 


SPOT  AND  ARC  WELDING 


According  to  these  rules,  J^-inch  rivets  would  be  re- 
quired for  14  "inch  steel  plates.  Referring  to  Table  XV 
it  will  be  noted  that  the  average  ultimate  tensile  of  the 
spots  made  was  approximately  17,000  pounds.  For 
inch  steel  plates  ^-inch  rivets  are  required.  Table  XVI 
shows  an  average  ultimate  tensile  of  31,760  pounds  for 
a  spot  in  ^-inch  steel  plate.  For  J^-inch  steel  plates 
inch  rivets  are  required.  Table  XVII  gives  an  average 
ultimate  tensile  of  39,010  pounds  for  a  spot  in  ^-inch 
steel  plate.  For  )^-inch  steel  plates  J/g-inch  rivets  are 
required.  Table  XVIII  gives  an  average  ultimate  ten- 
sile of  37,603  pounds  for  a  spot  in  ^-inch  steel  plate. 
These  averages  are  over  the  whole  test,  including  the 
short  and  medium  time  given  two-thirds  of  the  spots. 
The  averages  would  be  excessive  as  compared  to  the 
single  shear  of  the  appropriate  rivet  if  only  the  best  spot 
welds  were  taken.  For  ^-inch  steel  plates  1-inch  rivets 
are  required.  Table  XIX  gives  an  average  ultimate  of 
61,500  pounds  for  a  spot  in  ^-inch  steel  plate.  If  this 
data  were  composed  of  isolated  tests  then  questions 
might  be  raised  as  to  the  process,  but  these  tabulations 
are  repetitions  with  no  special  considerations  other  than 
that  of  assuring  uniformity. 

Take  the  average  of  spots  in  Table  XX,  represent- 
ing double  shear:  in  the  case  of  steel  rivets  a  double 
shear  is  not  twice  the  single  shear,  but  for  argument 
agree  that  it  is.  This  would  mean  that  the  shearing 
stress  of  two  ^-inch  steel  rivets  was  51,200  pounds.  The 
average  of  two  spots  in  ^-inch  steel  plate  is  a  little  more 
than  double  the  single  spots,  78,683  pounds.  The  ten- 
sile strength  of  two  spots  in  ^-inch  steel  plate  is  more 
than  the  tensile  strength  of  three  ^-inch  rivets  based 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  91 

on  multiplying  the  single  shear  of  a  %-inch  rivet  by  3. 
It  is  not  known  whether  the  shear  of  three  ^-inch  rivets 


has  ever  been  definitely  established,  but  comparative 
tests  made  during  this  demonstration  would  lead  to  the 
opinion  that  the  ultimate  tensile  would  be  much  less.  It 
seems  unnecessary  to  note  in  the  same  table  that  the 
average  ultimate  tensile  of  three  spots  in  J^-inch  steel 
plate  was  100,433,  although  the  last  set  of  spots  (No.  6) 
was  not  pulled  to  its  ultimate. 

An  interesting  set  of  tests  with  three  and  four  thick- 
nesses of  various  size  plates  was  contemplated  when  the 
demonstration  was  brought  to  a  close.  It  is  reasonable 
to  assume  that  if  the  rated  voltage  had  been  supplied  to 
the  duplex  spot  welder,  this  machine  would  have  welded 
three  and  four  thicknesses  of  ^-inch  plate.  Undoubt- 
edly the  same  uniformity  of  spot  welding  would  have 
followed  the  results  as  shown.  It  is  needless  to  speculate 
on  what  this  apparatus  could  do,  it  is  sufficient  to  record 
here  its  performance. 

One  of  the  best  practical  results  was  the  discovery 
of  a  fairly  simple  and  non-destructive  method  of  in- 
specting spot-welded  work  after  completion.  During 
the  tests  it  was  suggested  that  this  might  be  accomplished 
by  punching  a  hole,  or  holes,  on  the  line  of  demarkation 
of  the  spot  weld.  A  number  of  experiments  was  made 
which  gave  confidence  in  the  method.  In  finished  work 
these  test  samples  could  be  taken  of  a  reasonable  number 
of  spots  and  with  sufficient  variation  to  assure  that  the 
work  was  uniform  and  well  done.  To  further  empha- 
size this  method  of  inspection  the  ship's  floors  previously 
mentioned  were  sent  to  the  shipyard  and  a  request  made 
for  an  inspection  of  this  nature  of  independent  parties. 


92  SPOT  AND  ARC  WELDING 

It  was  known  by  those  who  had  followed  the  work  of 
spot  welding  that  there  were  good,  bad,  and  indifferent 
spot  welds  made,  and  the  intention  was  to  observe  how 
closely  this  method  of  inspection  could  be  relied  upon. 
The  results  more  than  exceeded  expectation.  The 
punchings  showed  all  degrees  of  welds.  The  finished 
article  is  not  greatly  injured  by  this  method  as  the 
punched  hole  can  be  refilled  by  either  spot  welding  a 
stud,  refilling  by  means  of  the  metallic  electrode,  or 
by  riveting. 

General  Comment. — There  are  two  primary  and  seri- 
ous considerations  to  be  given  the  process  of  heavy  spot 
welding.  They  are  briefly,  electrode-tip  protection  and 
the  preparation  of  materials  to  be  welded.  These  two 
points  are  closely  interlocked  and  greatly  circumscribed 
by  our  lack  of  proper  metals  or  knowledge  of  known 
metals.  There  are  two  secondary  considerations  which 
may  be  easily  improved  upon  and  which  may  be  stated 
briefly:  (1)  The  separation  of  the  electrodes,  and  (2) 
the  shape  of  the  head  of  the  spot  welder.  These  sec- 
ondary matters  are  mixed  with  questions  of  the  appli- 
cability to  shipbuilding  and  shop-production  methods. 

"Fig.  22  illustrates  roughly  the  type  of  electrode-tip 
protection  used  on  the  12-inch  welder  with  which  the 
early  tests,  including  the  ship's  floors,  were  made.  It 
consisted  of  a  strip  of  soft  copper  which  covered  and 
conformed  to  the  top  of  the  electrode.  When  this  strip 
was  worn  down  it  could  be  renewed  by  slipping  out  the 
steel  through-bolt.  The  difficulties  that  were  met  with 
in  practice  were  the  freezing  "  of  the  copper  strip  to 
the  electrode,  thus  requiring  it  to  be  chiseled  off,  and 
the  deformation  of  the  electrode  itself  when  under  severe 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  93 


working  strains  as  well  as  a  result  of  the  method  of  break- 
ing away  the  strip  from  it.  This  latter  necessitated 
either  the  removal  of  the  electrode  and  the  machining 
of  same  or  the  filing  or  truing  of  the  electrode  tip  before 
replacing  the  copper  strip.  This  design  was  modified 
and  much  improved  upon  for  the  27-inch  and  the  duplex 
machines.   A  steel  collar  was  fitted  to  the  electrode  by  a 


THROUGH-BOLT 


^COPPER  STRAP  '/l6 

] 


^OPPER  ELECTRODE 


ELECTRODE  WITH  COPPER  STRAP 

Fig.  22. — Electrode  with  copper  strap. 

coarse  thread  and  was  removable  by  means  of  a  spanner 
wrench.  This  steel  collar  securely  held  separable  tips  in 
close  contact.  As  these  tips  were  pyramidal  in  form  the 
crushing  pressure  deformed  the  tip,  but  did  not  affect 
the  electrode  proper.  The  tips  may  be  re-machined, 
and  as  they  go  through  an  annealing  process  in  the  act 
of  spot  welding  they  should  do  duty  several  times  before 
final  scrapping.  Their  cost  is  insignificant  as  compared 
to  the  electrode  cost  or  the  work  which  they  are  instru- 
mental in  performing.    It  was  found  essential  in  the 


94 


SPOT  AND  ARC  WELDING 


uniformity  tests  of  the  heavy  materials  to  replace  these 
tips  quite  frequently,  and  if  this  is  found  necessary  in 
regular  production  work  it  raises  a  serious  problem  as 
to  the  quick  action  of  the  process.  Further  develop- 
ments will  be  needed  to  solve  this  problem,  although  sug- 
gestions having  in  view  automatic  attachments  for 
renovating  the  tips  have  been  made. 

Naturally  a  great  reduction  in  the  number  of  tip 
renewals  is  accomplished  by  the  proper  preparation  of 
the  surfaces  of  the  materials  coming  in  contact  with  them. 
The  tests  at  Pottstown  proved  this  and  justified  the 
opinion  of  the  designer  of  these  machines.  The  subject 
raises  a  large  question.  The  suggestion  in  practical 
steel  shops  of  cleaning  the  surfaces  of  steel  plates  and 
shapes  brings  down  upon  the  spot-welding  process  a 
cloud-burst  of  opposition.  Three  methods  for  cleaning 
steel  have  been  brought  forward,  but  none  are  looked 
upon  as  solving  the  difficulty.  By  pickling,  that  is,  dip- 
ping the  steel  in  acid,  the  mill  scale  and  rust  may  be 
removed.  The  surfaces  may  be  cleaned  by  sand-blast, 
or  they  may  be  prepared  as  in  these  tests  by  the  use  of  a 
portable  air  grinder.  The  first  proposal  necessitates  a 
large  installation  expense  and  causes  delay.  The  second 
is  a  dangerous  operation  to  perform  on  a  large  scale  in 
an  open  shop,  as  the  flying  sand  or  dust  particles  enter 
the  small  parts  of  adjacent  machinery  as  well  as  affect 
neighboring  workmen.  The  last  proposal  is  feasible, 
could  be  done  while  other  material  is  going  through  the 
spot-welding  process  and  would  not  be  excessive  in  cost. 
The  opponents  of  the  spot-welding  process  cannot  but 
believe  that  this  is  an  awkward  makeshift.  There  is  a 
probable  solution  in  a  suggestion  made  to  equip  the 


DEMONSTRATION  OF  HEAVY  SPOT  WELDING  95 


spot-welding  machine  with  an  automatic  grinder  under 
the  control  of  the  operator.  This  method  would  permit 
the  operator  to  be  the  judge  as  to  the  fitness  of  the  mate- 
rial and  give  him  the  option  of  saving  time  either  by 
cleaning  the  materials  or  by  more  frequent  renewals  of 
the  electrode  tips.  Besides  this  utilitarian  advantage  of 
clean  steel  for  welding  there  is  a  humanitarian  reason. 
When  there  is  an  accumulation  of  rust  or  mill  scale  next 
to  the  electrodes  a  higher  resistance  is  provided  at  the 
point  of  contact.  The  desired  place  for  this  high  resist- 
ance is  between  the  plates  being  welded.  Accompany- 
ing the  high  resistance  at  the  electrodes  the  instantaneous 
production  of  intense  heat  causes  the  slag  to  be  thrown 
out  with  great  violence.  This  condition  is  dangerous  for 
the  operator,  not  only  for  his  eyes,  which  may  in  time  be 
affected  by  the  radiant  energy,  but  also  to  his  body  into 
which  may  enter  the  fine  slivers  of  molten  slag. 

Though  secondary  because  they  appertain  to  me- 
chanical features,  yet  important  in  that  they  are  neces- 
sary, the  distance  between  the  electrode  tips  in  machines 
designed  for  all-around  work  should  be  readily  adjust- 
able. In  the  apparatus  just  described  this  distance  was 
fixed  and  provision  was  made  to  fit  the  electrodes  so 
that  they  could  be  removed  from  their  holders,  thus 
allowing  for  the  placement  of  the  machine  over  obstruc- 
tions, and  the  replacement  of  the  electrodes  when  the 
work  and  machines  were  properly  set.  Undoubtedly 
such  an  arrangement  would  be  awkward  in  any  steel 
fabricating  shop.  Time  is  an  essential  element  in  all 
production  work.  The  correction  of  this  mechanical 
difficulty  in  new  designs  is  too  simple  not  to  be  insisted 
upon.   The  shape  of  the  head,  or  more  descriptively  the 


96 


SPOT  AND  ARC  WELDING 


nose,  of  the  machine  should  be  such  as  to  permit  the 
electrodes  to  function  in  very  close  quarters.  The  at- 
tachment of  angles  to  plates,  angles  to  angles,  two  angles 
on  opposite  sides  of  the  same  plate,  are  common  con- 
nections in  steel  construction.  It  is  particularly  neces- 
sary for  this  application  that  the  electrodes  be  quickly 
adjustable  and  that  they  be  easy  to  manipulate  in  cor- 
ners and  along  bounding  angles.  Although  the  elec- 
trodes of  the  12-inch  welder  had  to  be  changed  in  order 
to  bring  them  in  the  proper  position  for  welding  the 
boundary  angles  of  the  ship's  floors,  it  proved  what  was 
one  of  the  greatest  previous  objections  to  the  process, 
namely,  that  a  good  caulking  edge  could  be  left  on  the 
angle  after  spot  welding.  As  a  matter  of  fact,  a  good 
weld  cannot  be  made  on  edges  without  danger  to  the 
operator  due  to  the  throwing  of  melted  slag.  This  me- 
chanical difficulty  can  be  overcome  in  as  simple  a  manner 
as  the  adjustability  of  the  electrodes,  and  should  be  called 
for  in  new  designs  of  apparatus. 


CHAPTER  V 


General  Applications  of  Arc  Welding 

Those  who  began  an  investigation  into  the  applica- 
tion of  arc  welding  in  1917-18  were  naturally  surprised 
at  the  wide  use  of  the  process  in  repair  work  and  cer- 
tain manufactures.  Indeed,  for  both  land  and  marine 
repairs  the  success  of  many  of  the  applications  had  war- 
ranted its  approval  by  conservative  inspection  bureaus 
and  frequently  insisted  upon  by  the  owners  in  preference 
to  older  and  more  tried  methods.  It  was  for  this  reason 
that  the  United  States  Navy  Department  adopted  the 
process  for  the  quick  repairs  made  to  the  damaged  ma- 
chinery of  the  interned  German  ships,  and  the  success 
accruing  from  this  work  lent  impetus  to  the  proposals 
for  its  extension  to  shop  construction.  Although  these 
apphcations  ^  are  now  fairly  well  known  and  recently 
have  received  a  greater  publicity,  it  may  be  well  to 
briefly  review  them. 

Repair  Work. — There  are  three  interesting  points 
connected  with  this  subject:  (1)  Ease  of  application, 
(2)  the  vital  nature  of  the  repairs,  and  (3)  the  cost. 
The  first  and  third  items  caused  the  introduction  of  the 
process,  the  second  item  was  the  effect  of  its  continued 
success.  Engineers  associated  with  business  men  will 
readily  put  into  effect  an  innovation  that  carries  with  it 
the  dual  saving  of  time  and  money  without  involving 
great  danger,  but  a  similar  group  will  refuse  to  establish 
as  a  regular  industrial  practice  a  method  that  will  hazard 


^ "  Electric  Arc  Welding,"  Lincoln  Electric  Company,  Cleveland,  Ohio. 
7  97 


98 


SPOT  AND  ARC  WELDING 


the  lives  of  those  who  as  a  general  rule  are  innocent  of 
the  means  employed. 

The  majority  of  repairs  are  usually  required  for 
component  parts  of  large  pieces  of  machinery.  The 
older  methods  of  repair  made  it  necessary  to  disassemble 
the  machinery  to  obtain  either  the  broken  or  worn  part, 
or  to  expose  it  for  access.  In  turn,  indirect  expense  was 
caused  not  only  by  the  damage  done  by  the  taking  apart 
of  the  machine,  but  also  by  the  reassembling  of  those 
parts  which  were  in  no  sense  injured.  This  indirect 
charge  has  been  the  most  frequent  factor  of  dispute  in 
the  comparison  of  costs,  not  only  in  the  case  of  arc- 
welding  applications,  but  in  many  other  lines  of  engi- 
neering. It  is  not  an  uncommon  occurrence  to  discover 
that  the  work  of  demolition  has  cost  as  much  as,  or  more, 
than  the  cost  of  the  new  construction.  No  wonder,  then, 
that  the  electric  arc,  which  is  easily  brought  to  the  work 
and  there  produces  a  localized  welding  temperature,  was 
eagerly  accepted.  In  the  metallic-arc  process  the  actual 
tools  required  for  the  operator  are  a  screen,  a  wire  brush, 
a  hammer  and  chisel,  and  the  electrode  holder  with  its 
flexible  lead.  A  bundle  of  electrodes  near  at  hand  com- 
plete the  outfit  needed  at  the  work.  Back  of  these  local 
tools  provision  must  be  made  for  the  proper  electrical 
conditions.  In  American  practice  this  takes  the  form  of 
a  motor  generator  for  direct  current  and  a  transformer 
for  alternating  current.  This  machinery  end  of  the  tool 
for  a  single  operator  is  not  so  large  nor  heavy  that  it  can- 
not be  made  semi-portable  and  thus  provide  flexibility. 

In  very  large  installations  the  machinery  end  of  the 
arc- welding  tool  may  be  of  a  size  to  supply  many  welders, 
in  which  case  the  equipment  may  be  made  stationary  and 


GENERAL  APPLICATION  OF  ARC  WELDING  99 


the  electrical  circuit  distributed  to  plug  boards  for  the 
individual  operators.  So  in  any  desired  manner  the  tool 
may  be  brought  easily  to  the  work  and  the  broken  or 
used  parts  of  the  complicated  machinery  may  be  re- 
paired rapidly  and  safely  in  place. 

Many  of  the  large  railroad  systems  of  this  country 
have  employed  arc  welding  in  the  vital  repairs  to  loco- 
motives, which  is  being  extended  rapidly  to  freight  and 
passenger  cars.  This  means  that  millions  of  people  are 
being  carried  across  country  often  at  high  speed,  around 
curves,  and  up  and  down  grades  with  the  strains  and 
stresses  of  such  work  resisted  by  a  jointure  carefully 
made  by  the  electric  arc.  The  boilers  and  stern  posts  of 
ocean-going  vessels  are  repaired  by  the  same  method. 
In  addition  to  this,  street  railways  are  employing  the 
process  for  the  maintenance  of  tracks  and  cars,  and  ma- 
chine-shops for  the  repair  of  machine  tools.  If  these 
instances  were  chance  experiments  there  would  be  cause 
for  questioning  the  further  use  of  this  process,  but  what 
is  referred  to  here  is  now  established  practice  and  has 
been  an  accepted  method  for  many  years.  In  the  case 
of  locomotive-boiler  repairs  the  records  indicate  that 
electric-arc  repairs  exceed  the  allowed  use  of  the  original 
boiler  material. 

As  to  the  cost  of  arc-welding  repairs  and  a  compari- 
son with  the  older  methods,  the  preceding  remarks  give 
an  indication  which  is  quite  true,  namely,  that  they  are 
very  much  less.  In  round  figures  it  is  roughly  estimated 
to  save  between  50  and  60  per  cent.  The  Chicago,  Rock 
Island  and  Pacific  Railroad  kept  excellent  detail  ac- 
counts when  introducing  electric  welding.^ 

^ "  Railway  Electrical  Engineer,"  E.  Wanamaker,  1918. 


100 


SPOT  AND  ARC  WELDING 


As  an  illustration,  it  cost  this  railroad  by  the  old 
method  to  repair  wheel  spokes  $1276.80,  and  by  electric 
welding  $35.08,  a  saving  of  $1241.72;  for  repair  cracks 
in  tanks  by  the  old  method  $372.69,  by  the  electric  arc 
$36.16,  a  saving  of  $337.53;  for  filling  worn  spots  by 
the  old  method  $2677.80,  by  the  electric  arc  $329.60,  a 
saving  of  $2348.20.  These  are  a  few  items  of  a  large  list. 
In  a  simimary  for  the  year  it  is  shown  that  the  cost  by 
other  methods  would  have  amounted  to  $171,279  as 
against  arc  welding  $24,912.36,  a  saving  for  the  year  of 
$146,366.64.  There  may  be,  and  probably  are,  other  as 
significant  figures,  but  these  alone  are  considered  proof 
enough  not  only  of  the  cost  but  of  the  other  two  factors 
which  are  just  as  important,  the  ease  of  the  application 
and  the  seriousness  of  the  work  performed. 

Examples. — The  following  applications  of  arc  weld- 
ing for  repairs  may  give  an  idea  of  the  extended  use  of 
the  process.  In  steel  foundries  it  is  fovmd  difficult  to 
avoid  sand  spots,  blow  holes,  and  shrinkage  cracks  in  the 
finished  steel  castings.  It  is  an  expensive  process  and 
not  only  would  cause  a  higher  cost  if  defective  work 
were  scrapped  and  recast,  but  also  would  involve  a  delay. 
Such  defects  are  readily  and  satisfactorily  repaired  with 
the  electric  arc,  either  carbon  or  metallic.  By  means  of 
the  carbon  arc  utilized  for  pre-heating,  it  is  also  possible 
to  employ  the  process  for  the  same  conditions  in  the 
manufacture  of  grey  iron  and  malleable  castings.  Ref- 
erence has  already  been  made  to  railroad-shop  repairs 
where  established  use  is  made  of  this  process  for  the 
repair  of  engine  side  rods,  brake  fulcrum,  eccentric 
crank,  side  frames,  flues  of  boilers,  fire  box,  mud  ring, 
engine  cross  head,  bumper  beams,  brake-shoe  heads,  pis- 


GENERAL  APPLICATION  OF  ARC  WELDING  101 


ton  cross  heads,  motion  frames,  yokes  and  spokes  of 
wheels,  building-up  flanges  on  wheels,  etc.  A  list  three 
or  four  times  this  size  could  be  cited.  Marine  repairs  are 
usually  those  connected  w^ih  the  boilers,  the  rudder  post 
and  in  some  exceptional  cases  to  small  portions  of  the 
hull  plating.  In  street-railway  work  much  work  is  done 
in  building  up  the  rails  and  worn  parts  of  cross-overs. 
Worn  down  armature  shafts,  side  frames  of  trucks,  and 
gear  cases  are  also  repaired  by  this  process.  In  forge 
shops  the  metallic  arc  is  being  used  not  for  improving 
the  strength  of  the  forging,  but  to  give  it  a  good  appear- 
ance. Small  defects  are  apt  to  result  from  the  forging 
operation,  especially  in  forgings  for  automobiles.  These 
can  be  neatly  corrected  by  this  process.  In  the  large  or 
small  machine-shop  the  large  machine  tools  as  well  as  the 
small  hand  tools  may  be  quickly  put  back  in  service  and 
often  result  in  a  much  longer  effective  life  when  skill- 
fully arc  welded.  Bolt  holes  become  worn,  shafting  in 
motors  (particularly  alternating-current  motors  of  the 
induction  type  with  small  air  gap)  wear  down  in  the 
bearings  to  the  point  of  injury  to  the  armature  windings, 
bearing  surfaces  on  slides  and  cams  wear  away  in  the 
same  manner.  These  and  many  more  cases  are  conveni- 
ently corrected  by  building  up  the  surfaces  with  the 
metallic  arc  and  then  turning  the  pieces  in  a  lathe  to  the 
original  dimension.  "  Steel  mills  have  found  it  eco- 
nomical to  install  arc  welders  for  the  purpose  of  repair- 
ing wobblers  in  the  rolling  mill.  Work  is  also  being  done 
successfully  in  the  working  surfaces  of  the  roll." 

Manufacturing. — Three  characteristics  of  this  proc- 
ess brought  it  to  the  attention  of  manufacturers:  (1)  Its 
secrecy,  (2)  its  adaptability,  and  (3)  its  low  cost. 


102 


SPOT  AND  ARC  WELDING 


As  the  rivet  was  for  many  years  the  best-known 
method  of  joining  metals  either  very  thin  or  of  moder- 
ate thickness  where  a  medium-strength  joint  was  re- 
quired, this  became  the  estabhshed  practice.  As 
commercial  competition  grew  the  manufacturer  sought 
means  to  reduce  his  costs  so  that  his  selling  price  would 
reward  him  with  the  contract.  More  than  this,  he  de- 
sired that  this  be  brought  about  through  some  process 
that  for  a  time  would  remain  hidden  to  his  competitors. 
The  electric  arc  allowed  this  because  the  manufacturer 
could  develop  all  the  apparatus  and  tools  in  his  own 
shop  and  design  them  for  his  own  special  production.  It 
was  not  necessary  for  him  to  divulge  his  needs  to  the 
makers  of  electrical  machinery  nor  the  builders  of  stand- 
ard arc-welding  apparatus.  In  this  manner  his  special 
method  of  manufacture  was  concealed  and  his  secret 
safeguarded.  Manufacturers  of  arc-welding  appa- 
ratus will  admit  that  of  these  applications  they  have 
little  knowledge. 

More  than  this,  the  manufacturer  found  that  the 
electric-arc  process  was  adaptable.  Whatever  his 
methods  had  been  the  first  cost  of  the  apparatus  was  of 
no  concern  in  the  benefits  both  of  reduced  costs  and  the 
elimination  of  competition.  Besides  this,  the  arc-welding 
tool,  like  any  new  tool,  gave  promise  of  greater 
possibilities.  It  could  be  safely  handled  for  repetition 
work  by  ordinary  operators,  and  the  future  promised 
some  form  of  automatic  machine.  Other  methods  such 
as  gas  welding  were  tried  and  found  both  expensive  and 
dangerous.  By  experimentation  with  different  composi- 
tions of  electrodes,  by  varying  the  electric  current,  by 
the  use  of  coating  on  the  electrodes,  and  by  suitable 


GENERAL  APPLICATION  OF  ARC  WELDING  103 


selection  of  electrode  size  for  different  thicknesses  and 
kinds  of  material,  the  manufacturer  had  a  tool  which 
needed  only  ingenuity  to  uphold  his  production  on  a 
paying  basis. 

The  savings  in  cost  of  this  application  are  impossible 
to  obtain.  The  characteristic  mentioned  above  precludes 
anything  more  than  assumption.  The  fact  that  this 
process  is  employed  must  be  the  best  evidence  that  it  is 
the  cheapest  process  now  available.  To  those  acquainted 
with  the  riveting  process  there  is  no  question  that  adding 
the  cost  of  drawing  to  the  finished  product  there  is  no 
competition  with  electric-welding  processes.  In  the  case 
of  gas  welding  it  is  to  be  remembered  that  the  arc  can 
weld  where  the  gas  flame  cannot,  and  vice  versa.  This 
last  expression  should  probably  be  restricted  to  welding 
only,  as  it  is  possible  to  cut  steel  with  either  the  carbon 
or  metallic  arc.  From  this  it  will  be  seen  that  to  compare 
gas  welding  with  arc  welding  it  is  requisite  that  the  work 
be  common  to  the  two  processes.  When  this  is  done  the 
consensus  of  opinion  is  that  the  electric  arc  is  cheaper. 
Direct  comparison  of  costs  between  oxy-acetylene  and 
metallic  arc  welding  have  been  made,  but  such  costs  are 
not  of  great  value  in  that  the  conditions  are  changing. 
After  all,  in  general  manufacturing  other  elements  often 
take  precedence  in  the  introduction  of  a  new  process,  not 
solely  because  they  have  the  elements  of  money  saving 
so  much  as  money  making. 

Examples. — The  electric  arc  is  much  used  in  general 
boiler  shops.  Here  are  built  tanks,  vats,  tumbling  bar- 
rels, wagon  tanks,  oil  stills,  and  several  more  specialties 
of  a  similar  kind.  Other  shops  have  used  the  arc  for 
manufacturing  gear  cases,  automobile  frames,  street-car 


104 


SPOT  AND  ARC  WELDING 


entrances,  garage  heaters,  steel  bed  plates  for  support- 
ing machinery,  and  a  long  list  of  minor  parts  of  appa- 
ratus for  oil  and  sugar-making  machinery.  The 
construction  of  transformer  tanks  with  the  arc  has  for 
many  years  superseded  other  methods  and  the  combina- 
tion of  hand  and  automatic  arc  welding  constitutes  an 
advance  over  all  other  methods  tried.  This  method  was 
found  superior  because  of  its  reliability  in  service  and 
its  economy  in  production.^ 

^ "  Electric  Arc  Welding  in  Tank  Construction,"  R.  E.  Wagner,  General 
Electric  Review,  December,  1918. 


CHAPTER  VI 


Discussions  on  Arc  Welding 

Aroused  by  the  interest  in  the  rapid  extension  of  arc 
welding  in  the  industries  as  well  as  impelled  by  patriotic 
feelings,  a  group  of  men  gathered  to  discuss  the  funda- 
mentals of  the  art.  Although  this  group  was  engaged 
in  widely-separated  occupations  and  was  sincere  in 
wishing  to  cooperate  for  such  a  good  purpose,  it  was 
discerned  that  the  differences  of  opinion  generally  ran 
in  parallel  lines,  indicating  that  great  latitude  was  per- 
mitted for  volitional  selection.  Under  such  conditions 
group  action  of  a  determining  character  was  not  to  be 
expected.  It  was  not  an  established  body.  That  is  to 
say,  each  meeting  constituted  itself  into  a  new  meeting 
to  discuss  the  different  phases  of  some  subject  and,  al- 
though a  few  members  were  in  regular  attendance,  new 
members  were  admitted,  which  reacted  not  only  to  re- 
open previous  discussions,  but  also  to  stay  the  pursuit  of 
investigation  by  new  suggestions.  This  explanation  is 
made  so  that  proper  values  may  be  placed  upon  the  fol- 
lowing outline  of  discussions  which  took  place  in  1918. 

Eoctension  to  Thick  Steel  Plates, — Doubt  existed  in 
the  minds  of  conservative  experts  whether  uniform  re- 
sults could  be  expected  in  the  welding  of  ^-inch  steel 
plates  of  the  composition  used  in  shipbuilding  in  this 
country.  Certain  members  of  the  group  reported  that 
compositions  of  steel  had  been  experimented  with  and 
they  had  found  it  practically  impossible  to  successfully 

105 


106 


SPOT  AND  ARC  WELDING 


weld.  Other  more  radical  supporters  of  the  process 
made  hght  of  this  with  the  remark  "  that  you  can  elec- 
trically weld  anything."  The  need  was  clear  for  a  de- 
termination of  the  fact  that  ship's  steel  of  a  thickness  of 
y2  inch  could  be  successfully  welded.  With  this  funda- 
mental question  was  coordinated  the  query  whether  firms, 
who  performed  welding,  could  turn  out  equal  results 
despite  the  different  methods  pursued.  A  sub-committee 
was  appointed  to  follow  the  practical  details  which  con- 
sisted in  obtaining  ship's  steel  plates  ^  inch  thick,  have 
them  prepared  for  arc  welding  (double  V,  butt  joint), 
and  make  observations  of  the  welding.  These  firms  were 
given  entire  freedom  in  the  methods,  materials,  oper- 
ators, electrodes,  current,  etc.  In  some  cases  two 
samples  were  made,  one  with  a  reinforced  weld  and  the 
other  with  the  reinforcement  machined  down.  This  col- 
lection of  samples  was  sent  to  the  Bureau  of  Standards 
for  physical  test — tensile,  torsion,  vibration,  and  bend- 
ing. The  results  confirmed  the  opinion  that  successful 
welds  could  be  made  in  this  material.  Many  of  the 
samples  exceeded  the  yield  point  of  the  original  material 
as  well  as  ultimate  strength.  In  a  number  of  cases  the 
elongation  in  two  inches  expressed  in  per  cent,  ap- 
proached fifty  per  cent,  of  the  original  material,  and  one 
test  piece  was  made  with  alternating  current  at  25  cycles 
bent  in  the  weld  to  an  angle  of  78  degrees.  The  rein- 
forced welds  all  showed  a  higher  ultimate  tensile  than 
the  machined-down  test  pieces.  The  yield  point  in 
pounds  per  square  inch  of  the  original  plate  was  38,400. 
Some  of  the  reinforced  samples  gave  yield  points  of 
42,460,  40,280,  40,480,  42,200,  39,000,  46,440,  and 
44,700  pounds.   Five  machined-down  samples  showed  a 


DISCUSSIONS  ON  ARC  WELDING  107 


yield  point  of  39,000,  39,000,  38,400,  42,400,  and  41,800 
pounds.  The  original  plate  tested  to  an  ultimate  tensile 
of  64,700  pounds  per  square  inch.  Reinforced  welds 
showed  results  as  follows:  65,470,  65,400,  66,480,  66,400. 
None  of  the  machined  samples  equalled  nor  exceeded 
the  ultimate  tensile  of  the  original  plate,  but  three 
samples  reached  62,600,  62,800,  62,700.    These  tests 


Fig.  23. — Car  coupler  used  in  railway  work  before  arc  welding. 


were  looked  upon  as  practical,  formed  the  base  line  for 
further  argument,  and  suggestions  were  made  both  for 
improvement  in  testing  and  for  extension  of  results. 
The  outcome  was  the  preparation  of  a  more  elaborate 
program  of  tests  with  like  materials,  but  with  more  uni- 
form welding  conditions  and  the  elimination  of  some  of 
the  many  variables.  It  had  been  difficult  to  carry  out 
the  foregoing  tests  without  delay.  The  more  elaborate 
tests  were  by  their  nature  subject  to  greater  postpone- 
ment, and  as  a  consequence  were  halted  before  their 


108 


SPOT  AND  ARC  WELDING 


entire  completion.  Broadly  viewed  it  is  questionable 
whether  such  investigations  are  of  great  value  in  that  the 
arc-welding  operator  is  a  serious  hnk  in  the  chain.  All 
the  tests  of  manual  welding  made  by  others  would  prove 
little  to  the  man  who  wished  to  use  the  process. 

Composition  of  Electrode. — The  material  used  for 
electrode  wire  had  long  been  the  subject  of  investigation 
by  users  of  this  process.  Not  only  chemical  analyses  of 
the  electrode  wire  but  also  similar  analyses  of  the  de- 
posited metal  in  the  weld  were  made.  Side  by  side  with 
the  chemical  inquiry  ran  the  metallurgical.  It  was  true 
that  certain  alloyed  steels  gave  better  results  with  cer- 
tain compositions  of  steel  plate.  In  fact,  it  was  svig- 
gested  that  for  the  best  interests  of  shipbuilding  a  differ- 
ent composition  of  steel  might  be  required  on  the  basis 
of  its  weldability.  This  suggestion  would  be  difficult  in 
view  of  the  commercial  conditions  which  likewise  dic- 
tated the  composition  of  the  electrode  materials.  Doubt- 
less an  increased  demand  for  electrode  wire  for  special 
applications  might  ease  the  situation,  but  under  the  con- 
ditions the  user  must  accept  what  was  on  the  market. 
That  certain  desirable  results  in  welding  could  not  be 
attained  with  the  electrode  composition  as  furnished  is 
true,  and  one  manufacturer  was  unable  during  this  period 
to  duplicate  results  made  elsewhere.  There  resulted 
from  this  discussion  a  practical  specification  for  elec- 
trode wire.  This  instrument  was  issued  as  a  guide  to 
shipbuilders  who  wished  to  purchase  such  material.  The 
chemical  composition  was  such  as  to  include  all  of  the 
manufacturers,  and  the  test  requirements  were  made  to 
invite  the  manufacturers'  attention  to  the  need  of  a  dem- 


DISCUSSIONS  ON  ARC  WELDING 


109 


onstration  of  his  product  before  the  completion  of  the 
sale.    The  chemical  composition  is  as  follows: 


Design  of  Weld. — This  was  the  subject  of  special 
debate  because  of  its  bearing  upon  the  design  of  an  all- 
welded  ship.  The  type  of  joint,  the  design  of  weld,  the 
position  of  weld,  kind  and  type  of  weld,  all  required  in- 
vestigation before  the  naval  architect  could  make  draw- 
ings for  the  ship.  Early  in  the  proceedings  the  strap 
joint  was  considered  to  be  100  per  cent,  efficient  and  re- 
mained so  until  word  was  received  from  England  that 
the  butt  joint  was  better.  The  strap  joint  was  then 
questioned  as  to  the  order  in  which  the  three  seams  of 
welding  should  be  performed  which  led  the  discussions 
into  metallurgical  theories.  Not  quite  the  same  fate  was 
reserved  for  the  angle  of  bevel.  This  was  a  subject  upon 
which  many  differed.  Evidently  no  practical  action  was 
taken  to  settle  this  argument,  so  finally  it  was  left  to  the 
choice  of  the  designer.  As  the  amount  of  deposited 
metal  from  the  electrode  is  relative  to  the  size  of  the 
bevel,  and  as  the  goodness  of  the  weld  depends  on  the 
ease  given  the  operator  to  fuse  the  original  metal  with 
the  deposited  metal,  the  biting-in  effect,  this  point  bears 
no  small  ratio  to  the  final  results.  In  the  use  of  covered 
electrodes  practice  might  permit  a  different  angle  of 
bevel  or  with  special  electrode,  where  the  cost  was  ex- 
cessive, a  reduction  of  the  needed  deposit  of  electrode 
wire  would  greatly  affect  the  final  cost. 


Carbon    .  .  . 

Manganese 

Phosphorus 


Not  over  0.18 
Not  over  0.55 
Not  over  .05 
Not  over  .05 
Not  over  .08 


Sulphur 
Silicon 


110 


SPOT  AND  ARC  WELDING 


Associated  with  this  question  was  the  number  of 
layers  of  deposited  metal.  Though  the  generally  ac- 
cepted position  was  that  for  ^-inch  steel  plates,  one 
layer  was  not  the  proper  method  for  securing  the  best 
tensile  strength  of  weld,  yet  the  tests  showed  welds  made 
in  one  run  which  gave  results  as  high  as  62,600  pounds 


per  square  inch  ultimate  tensile.  There  were  very  few 
welds  made  in  two  layers  which  exceeded  this  figure. 
This  was  an  important  point,  because  it  directly  affected 
the  speed  of  welding,  one  of  the  main  factors  of  its 
economy.  Before  a  second  layer  of  deposited  metal  can 
be  run  in,  it  is  necessary  to  clean  thoroughly  the  top  sur- 
face of  the  first  layer.  If  much  slag  has  been  brought 
up  to  the  top  of  the  weld,  which  must  be  done  by  the 
welder,  it  requires  a  chisel  and  hammer  to  fully  clean 
this  surface.  In  the  case  of  slag-producing  electrodes, 
this  deposit  must  also  be  scrupulously  removed  before 


Fig.  24. — Car  coupler  used  in  railway  work  after  arc  welding  with  coated  electrode. 


DISCUSSIONS  ON  ARC  WELDING  111 


beginning  the  second  run  of  metal.  It  is  claimed,  and 
the  claim  has  elements  of  justification,  that  the  second 
layer  in  its  act  of  deposition  partly  anneals  the  first 
layer;  but  curiously  it  is  found,  except  with  special  proc- 
esses, that  annealing  does  not  greatly  improve  the  quali- 
ties of  the  weld.  If  there  is  no  virtue  in  adding  layer 
upon  layer  of  deposited  metal,  and  if  one  layer  will  pro- 
duce a  reliable  and  satisfactory  weld,  time  and  labor 
would  be  wasted.  This  question  has  been  left  to 
the  designer. 

In  a  like  category  were  the  discussions  on  the  posi- 
tions of  the  weld,  i.e.,  flat,  horizontal,  vertical,  and  over- 
head. The  extremists  held  that  overhead  welding  should 
be  done  only  by  specially  trained  men.  More  than  this, 
that  the  ordinary  man  should  not  be  trained  to  do  over- 
head welding.  The  intention  of  the  extremists  was  that 
in  order  to  train  operatives  quickly  it  was  a  waste  of 
time  to  expect  them  with  a  brief  training  to  make  suc- 
cessful welds  in  the  overhead  position.  Experience  in 
the  training  schools  for  welders  showed  advantages  for 
overhead  welding  as  a  method  of  practice  in  that  the 
student  was  more  confident  in  all  the  other  positions 
after  having  mastered  the  difficult  overhead  conditions. 
At  the  other  extreme  were  those  who,  having  experience 
with  handling  the  electrode,  asserted  that  the  position 
was  not  as  distressing  to  the  operator  nor  as  detrimental 
to  a  good  weld  as  generally  considered.  The  other  posi- 
tions, though  not  receiving  the  same  prominence  in  the 
argument,  were  not  as  easy  for  the  operator  as  supposed. 
The  flat  position  is  the  most  comfortable  and  conveni- 
ent, although  welders  may  be  found  who  prefer  the 
vertical  position.    The  horizontal  position  is  most  awk- 


112 


SPOT  AND  ARC  WELDING 


ward  and  in  difficult  places  requires  the  operator  to 
be  ambidextrous. 

From  the  tests  above  cited  attention  was  called  to 
the  difference  in  ultimate  tensile  strength  in  the  rein- 
forced weld  and  one  that  had  been  machined.  No  com- 
parisons were  made  with  a  flush  weld,  i.e.,  one  made  flush 
by  the  operator.  The  tests  show  quite  convincingly  the 
opinion  held  that  the  reinforcement  of  the  weld  added 
strength  to  the  joint.    With  this  point  established  it  is 


Fig.  25. — Bolster  used  in  railway  work  before  arc  welding. 


necessary  to  go  one  step  farther  and  determine  the 
amount  of  reinforcement  requisite  for  a  certain  strength 
of  joint  or  for  a  particular  application.  In  this  case  the 
particular  application  was  shipbuilding,  and  some  limit 
either  maximum  or  minimum  of  reinforcement  was 
essential.  In  this  as  in  the  case  of  the  angle  of  bevel, 
the  question  is  of  importance  in  that  it  means  consump- 
tion of  the  electrode  and  the  time  of  making  the  weld. 

Covered  Versus  Bare  Electrodes. — The  bare-metal 
electrode  process  was  introduced  about  1895  by  a  Rus- 
sian named  Slavianoff.    The  covered-electrode  process 


DISCUSSIONS  ON  ARC  WELDING  113 


bears  the  trade  name  of  Quasi-Arc  and  is  the  invention 
of  Mr.  Arthur  Strohmenger,  of  London.  Both  systems 
have  been  already  described.  The  Slavianoff  system  has 
been  used  in  this  country  for  many  years  and  it  is  stated 
by  one  authority  "  that  he  is  not  aware  of  any  user  "  in 
England.^  The  Quasi-Arc,  or  covered-electrode  sys- 
tem, was  only  recently  introduced  to  American  practice. 
It  was  natural  that  those  who  were  familiar  with  the 
working  capabilities  of  the  bare  electrode  should  insist 
upon  its  equal  performance  to  the  covered  electrode. 
When  a  physical  test  of  a  covered-electrode  weld  showed 
superior  qualities,  naturally  advocates  of  bare-electrode 
systems  hastened  to  exhibit  welds  that  would  equal 
or  surpass  the  new  competitor.  To  the  full  appreciation 
of  the  discussion  must  be  brought  the  commercial  atti- 
tude because  this  affects  directly  one  of  the  principal 
technical  points.  The  customary  practice  for  direct  cur- 
rent was  to  provide  a  "  striking  voltage  "  of  60  to  75 
volts.  Upon  this  practice,  standard  apparatus  in  this 
country  was  designed  and  built.  This  striking  volt- 
age "  corresponds  approximately  to  an  arc  voltage  rang- 
ing from  15  to  25  volts.  The  covered  electrodes  required 
a  "  striking  voltage  "  of  at  least  100  volts,  and  prefer- 
ably a  little  over,  giving  an  approximate  arc  voltage  of 
35.  Very  few  manufacturers  of  arc-welding  apparatus 
allowed  for  any  possible  adjustment  of  the  voltage  of 
the  welding  generator.  This  condition  reacted  severely 
on  the  rapid  introduction  of  the  covered  electrode.  De- 
spite this  condition  test  results  both  from  England  and 
in  this  country  indicated  very  clearly  that  for  alternat- 

^"  Electric  Welding,"  Thomas  T.  Heaton,  The  Journal  of  the  Inst,  of 
Mechanical  Engineers,  London,  February,  1919. 

8 


114 


SPOT  AND  ARC  WELDING 


ing  stresses  and  ductility  there  was  a  superiority  in  the 
use  of  a  covered  electrode.  The  experiments  of  British 
Lloyd's  in  electric  welding  were  all  made  with  this  type 
of  electrode,  and  the  process  was  approved  by  this  classi- 
fication society.  The  characteristics  of  resistance  to 
shock,  a  reasonable  ability  to  withstand  fatigue,  an  in- 
creased bending  angle  are  important  considerations  in 
the  applicability  of  a  welding  process  to  ship  construc- 
tion. The  claims  for  the  covered  electrode  were  based 
on  the  fact  that  the  covering  provided  a  slag  which  pro- 
tected both  the  electrode  and  the  deposited  metal  from 
oxidation.  The  result  was  that  in  the  hands  of  a  skilled 
operator  there  was  less  porosity  and  a  more  ductile  weld, 
retaining  at  the  same  time  good  tensile  strength. 

The  reported  results  soon  turned  the  attention  of 
investigators  to  the  advantage  of  some  form  of  protec- 
tion to  the  electrode.  Experiments  easily  performed 
showed  that  electrode  wire  that  was  not  smooth  running 
or  would  not  produce  good  welds,  if  heat  treated,  dipped 
in  acid  or  alkaline  solution,  would  become  better  or 
worse,  depending  upon  the  methods  used.  These  trials 
were  in  line  with  Kjellberg's  invention  which  provided 
an  electrode  coated  with  a  fusible  silica.  This  coating 
formed  a  flux  which  was  converted  into  a  gas  by  the 
heat  of  the  arc  and  therefore  left  no  slag  as  is  the  case 
with  the  Quasi-Arc  covered  electrode.  Coating  of 
the  electrode  now  came  into  style  and  the  results  of 
tested  welds  above  referred  to  showed  one  sample  in 
which  half  the  electrode  was  coated  with  a  special  solu- 
tion giving  unusual  bending  characteristics.  The  covered- 
electrode  sample,  though  not  giving  results  as  high 
as  this  particular  sample,  were  next  to  it  and  exceeded 


DISCUSSIONS  ON  ARC  WELDING  115 


all  the  others.  The  decision  of  British  Lloyd's  in  ap- 
proving this  process  of  covered  electrodes,  although  it 
threw  great  weight  in  its  favor,  has  not  caused  the  ad- 
herents of  the  bare-metal  electrode  to  relinquish 
their  position. 

Although  it  may  be  possible  to  successfully  weld  mild 
steel  for  ordinary  purposes  with  the  bare-steel  electrode 
and  thus  avoid  the  expense  of  covered  electrode,  where 
toughness  is  a  desirable  or  necessary  characteristic  of 
the  weld,  or  for  the  welding  of  steel  alloys,  a  special  coat- 


FiG.  26. — Bolster  used  in  railway  work  after  arc  welding  with  coated  electrode. 


ing  will  give  better  and  in  many  cases  the  only  successful 
results.  One  of  the  foremost  electric-welding  engineers 
in  this  country  has  lately  experimented  with  and  has  now 
achieved  much  success  with  coated  electrodes.  He  states : 
Regarding  the  chrome  steel  would  advise  that  we  have 
received  and  successfully  welded  with  chrome  steel, 
nickel,  vanadium,  manganese,  and  carbon.  Have  also 
welded  with  bronze  when  using  our  electrode  coating. 
We  have  received  patents  on  this  process  but  have  not 
as  yet  placed  any  coated  electrodes  on  the  market,  largely 
due  to  the  fact  that  it  was  difficult  to  obtain  alloy  elec- 
trodes during  the  war  (Fig.  26). 


116 


SPOT  AND  ARC  WELDING 


"  Recently  we  ran  some  tests  on  four  bare  mild  steel 
electrodes,  each  made  by  a  different  manufacturer. 
When  used  bare  it  is  impossible  to  secure  the  weld,  but 
with  our  coating  the  weld  is  very  successful.  Outside  of 
the  possibility  of  using  alloyed  steel,  and  all  results  at- 
tendant with  the  use  of  same,  our  chief  aim  has  been  to 
make  a  weld  in  which  the  added  metal  would  be  compara- 
tively free  from  oxidation.  This  would  give  us  a  weld 
possessing  much  greater  toughness  than  that  possessed  by 
the  bare-steel  electrodes.  It  is  needless  to  say  that  this 
toughness  imparts  a  quahty  very  much  to  be  desired,  and 
has  a  very  important  bearing  on  the  success  of  electric 
welds  to  withstand  fatigue."  ^ 

Direct  Current  Versus  Alternating  Current. — Apart 
from  the  fact  that  many  engineers  believed  that  arc  welds 
could  not  be  made  with  alternating  current,  their  argu- 
ments attacked  the  application  of  alternating  current 
from  three  sides :  (1)  Its  newness,  (2)  its  wasted  energy, 
(3)  its  difficulty  of  operation.  Direct  current  had  long 
held  the  field  and  hence  the  apparatus  and  tools  were 
familiar  to  both  engineers  and  operators.  The  design 
of  transformer,  unlike  power  transformers,  required  a 
large  leakage  reactance  in  order  to  stabilize  the  arc.  Due 
to  the  character  of  alternating  current  it  was  impossible 
to  weld  without  holding  a  short  arc.  This  is  a  requisite 
for  successful  welds  with  direct  current,  but  in  this  latter 
case  the  apparatus  gave  a  certain  tolerance  to  the  oper- 
ator, whereas  with  alternating  current  the  arc  position 
was  dependent  and  must  be  held  by  the  operator.  This 
required  more  practice,  greater  skill,  and  more  fatigue 

^  Comrrmnicated  to  the  Author  by  Mr.  E.  Wanamaker,  E.  E.,  Chicago, 
Rock  Island  &  Pacific  Railway,  September,  1919. 


DISCUSSIONS  ON  ARC  WELDING 


117 


for  the  operator.  If  the  operator  repeatedly  lost  his 
arc,  the  weld  would  be  porous  and  filled  with  blow  holes, 
and  the  opponents  of  alternating-current  welding 
claimed  that  by  the  nature  of  things  this  would  be  true. 

Of  this  latter  point  the  advocates  of  alternating- 
current  welding  made  much.  They  insisted  that  with 
it  you  could  only  weld  and  never  not  weld,"  as  in  the 
case  of  direct  current.  They  held  that  the  process  showed 
distinctly  a  "  biting-in  "  effect,  i.e.,  better  fusion  of  the 
original  metal  with  the  deposited  metal.  As  to  the  oper- 
ator, it  was  not  a  difficult  matter  to  train  those  who 
handled  the  direct-current  arc  and  that  a  number  of  old 
operators  claimed  a  preference  for  alternating  current. 
As  to  the  second  point  of  the  argument,  they  believed 
that  upon  development  the  low-power  factor,  or  poor 
efficiency,  would  be  greatly  impr.oved  and  in  some  in- 
stances claimed  that  the  power  factor  was  not  so  low  as 
to  put  the  process  out  of  the  running  as  compared  with 
other  systems.  To  this  end  they  made  tests  to  prove  that 
good  welds  could  be  made  with  any  frequency  and  at  the 
lower  frequencies  the  power  factor  would  be  better.  In 
answer  to  point  three,  while  admitting  the  "  newness," 
they  claimed  equality  as  far  as  the  application  to  new 
construction  work  was  concerned,  and  then  endeavored 
to  show  the  advantages  from  the  standpoint  of  economy 
in  first  cost,  continuous  operation,  and  upkeep.  As  it 
was  only  necessary  to  have  a  transformer  connected  to 
the  electrical-supply  leads  this  obviated  the  necessity  for 
rotating  machinery  and  gave  the  apparatus  a  more 
practical  portability. 

As  in  the  case  of  the  other  discussions  these  interest- 
ing points  were  never  clearly  determined.   No  compara- 


118 


SPOT  AND  ARC  WELDING 


tive  data  is  at  hand  to  indicate  whether  direct-current 
welding  is  faster  or  slower  than  alternating  current; 
whether  this  practical  advantage  is  benefited  in  either 
case  by  flux-covered  or  coated  electrodes;  whether  it  is 
more  difficult,  or  impossible,  for  the  ordinary  operator 
to  weld  in  all  positions,  including  overhead,  in  the  one 
system  than  the  other;  whether  the  practical  losses  in 
motor  generator  and  resistance  in  the  direct-current  sys- 
tem, other  things  being  equal,  compares  favorably  or  un- 
favorably with  the  alternating-current  system  and 
whether  there  are  physical  obstructions  to  the  training  of 
operators  that  would  make  the  alternating-current  sys- 
tem improbable  of  industrial  acceptance  without  assur- 
ance that  the  system  gave  promise  of  being  capable  of 
improvements  which  would  overcome  such  impediments. 
Individual  investigators  may  have  settled  all  of  these 
questions  to  their  own  satisfaction,  but  the  general  prac- 
titioner looks  in  vain  for  independent  authority.  Many 
more  claims  than  are  cited  here  are  made  by  both  parties 
to  this  controversy,  but  they  lead  into  the  field  of  theories. 

Testing  of  Welds. — Perhaps  no  subject  received  as 
much  consideration  both  by  suggestion  and  experimenta- 
tion than  the  discovery  of  some  practical  method  of  test- 
ing a  welded  joint.  Though  the  question  was  emphasized 
by  practical  men  who  wished  a  practical  method,  all  the 
exertions  were  toward  theoretical  or  laboratory  methods. 
Exhaustive  tests  were  made  with  delicate  apparatus 
upon  samples  containing  purposely  poor  and  good  weld- 
ing and  by  maintaining  certain  characteristics  constant. 
Methods  were  suggested,  such  as  measuring  the  mag- 
netic permeability,  the  change  in  hysteresis,  drop  in  volt- 
age, resistance.  X-ray  photographs,  etc.    The  practical 


DISCUSSIONS  ON  ARC  WELDING  119 


methods  were  by  hammering  the  welds  or  chipping  out 
small  portions  for  examination  or  by  wetting  a  cleaned 
portion  with  kerosene.  This  latter  test,  due  to  the  pene- 
trating qualities  of  kerosene,  would  indicate  porosity. 
The  theoretical  desire  was  to  determine  positively  the 
physical  characteristics  of  the  weld :  the  practical  desire 
was  to  convince  or  assure  those  who  inspected  the  work 
that  the  weld  was  sound.  A  little  more  was  needed.  The 
men  who  serve  as  inspectors  are  responsible  to  those 
above  them  in  authority,  and  it  is  necessary  that  a  prac- 
tical method  be  established  so  that  individual  responsi- 
bility, or  opinion  as  to  workmanship,  is  not  relied  upon 
for  serious  applications.  No  practical  method  of  testing 
long  seams,  such  as  those  that  would  be  encountered  in 
ship  construction,  have  as  far  as  is  known  been  devised. 
To  fill  all  the  compartments  of  a  merchant  vessel  for  the 
purpose  of  testing  joints  would  be  out  of  the  question, 
although  for  bulk-oil  vessels  this  is  now  done.  The  only 
practical  suggestion  advanced  is  that  the  inspectors 
should  be  trained  just  as  they  were  trained  to  inspect 
riveting  work.  If  a  man  knows  how  to  hold  an  electrode 
and  can  make  a  sound  weld,  no  other  man  could  deceive 
him  either  as  to  his  ability  as  a  welder,  or  the  quality  of 
work  that  he  was  performing.  Much  can  be  said  of  the 
comparative  merits  of  the  practical  methods  of  testing 
rivets.  But  it  is  not  necessary  to  extend  the  argument 
because  there  will  be  a  method  forthcoming  as  soon  as 
electric  welding  is  established  practice. 

Current  and  Electrode, — Although  the  manufac- 
turers of  apparatus  give  tables  showing  the  current  and 
electrode  diameter  for  varying  thicknesses  of  mild  steel, 
they  accompany  such  information  with  words  of  precau- 


120 


SPOT  AND  ARC  WELDING 


tion  to  the  operator  that  such  figures  are  only  approxi- 
mations. The  electrode  size  is  related  to  the  amount  of 
current  and  the  class  of  work.  The  amount  of  current 
is  not  necessarily  relative  to  the  thickness  of  the  plate, 
although  this  is  a  good  practical  guide  for  mild-steel 
plates  under  ^  inch.  The  design  of  joint  has  some  bear- 
ing upon  the  current  requirements,  as,  for  example,  the 
lap-joint,  which  undoubtedly  will  be  better  made  with  a 
gi'eatly  increased  current  over  that  necessary  for  the 
simple  double-bevel  butt-joints. 

In  the  tests  of  sample  welds  it  was  noticed  that  some 
of  the  best  results  were  secured  with  increased  current, 
and  this  observation  aroused  much  interest.  Investiga- 
tions by  individuals  showed  that  increased  current, 
through  a  range  of  80  to  27 5  amperes  with  all  other  con- 
ditions constant,  improved  the  tensile  strength  and  duc- 
tility. The  next  question  was  where  the  effects  of 
increased  current  terminated.  It  is  not  known  whether 
succeeding  experiments  have  determined  this  point. 

The  largest-size  electrode  suggested  in  practice  is 
3/16  inch  in  diameter.  A  5/32-inch  electrode  being  a 
popular  size  for  currents  ranging  from  approximately 
100  volts  to  190  volts,  and  used  for  mild-steel  plates  of 
from  ^  inch  to  ^  inch  in  thickness.  In  heavy  welding 
the  metal  is  deposited  in  layers,  sometimes  two  or  three, 
left  to  the  option  of  the  designer.  It  is  claimed  that^ach 
succeeding  layer  anneals  the  one  beneath  it  and  if  a  rein- 
forced layer  is  placed  on  top  it  will  complete  the  anneal- 
ing process  and  may  without  affecting  the  joint  be 
machined  down.  This  method  appealed  to  many  engi- 
neers as  a  long  and  tedious  process,  and  the  question 
arose  whether  a  weld  could  not  be  made  with  larger- 


DISCUSSIONS  ON  ARC  WELDING  121 


diameter  electrodes  and  accomplish  the  work  in  one  run. 
In  addition  to  the  explanation  of  the  annealing  effects 
of  the  layer  method  it  is  believed  that  with  an  electrode, 
say  of  3/8 -inch  diameter,  that  the  increased  current  would 
be  so  great  that  it  becomes  a  cutting  current,  and  con- 
trol of  the  arc  not  within  the  skill  of  the  operator.  That 
is  to  say,  that  the  arc  characteristic  would  be  such  that 
smooth  movement  at  short-arc  length  would  not  be  pos- 
sible, and  smooth  running  of  the  electrode  is  an  essential 
of  good  welding. 

Rigid  Versus  Non-rigid  Assembly. — The  question 
of  the  best  method  of  preparing  long  plates  for  seam 
welding  fell  into  two  groups:  those  whose  practice  war- 
ranted the  belief  that  welded  seams  could  be  made  when 
the  two  plates  were  rigidly  connected  either  mechani- 
cally or  by  means  of  widely-spaced  tack  welds,  and  those 
whose  practice,  though  not  denying  the  possibility  of 
rigid  assembly,  warranted  the  belief  that,  by  giving  the 
plates  room  for  expansion  and  contraction,  the  cooling 
stresses  (locked-in)  would  be  greatly  reduced  and  that 
more  uniform  success  would  result.  •  The  non-rigid  sys- 
tem provides  for  a  tapered  separation  between  the 
plates,  the  welding  beginning  at  the  small  end.  Clamps 
are  inserted  between  the  plates  and  hold  the  proper  dis- 
tance. The  operator  upon  releasing  them  observes  the 
rapidity  or  slowness  of  the  expansion  and  acts  in  accord- 
ance therewith,  ix,y  if  the  opening  closes  quickly  he 
hastens  his  welding,  or  if  it  is  slow  in  closing  he  waits. 
The  effects  of  expansion  and  contraction  are  observed 
and  cared  for  in  the  rigid  system  in  much  the  same  way 
with  this  difference,  that  usually  the  seam  is  not  made 
continuously  but  in  sections  which  permit  of  a  distribu- 


122 


SPOT  AND  ARC  WELDING 


tion  and  equalization  of  the  cooling  stresses.  The  marked  | 
effect  of  the  discussion  was  its  relation  to  ship  construc- 
tion, for  it  is  not  conceivable  how  the  non-rigid  system 
could  be  applied. 

Both  for  practical  evidence  of  the  ability  of  arc- 
welded  seams  in  ^-inch  steel  plate  to  withstand  shock 
and  fatigue  comparable  to  those  met  in  ship  design,  as 
well  as  to  put  the  non-rigid  system  to  test,  a  12-foot 
tank  ^  of  ^-inch  tank  steel  was  built  and  tested.  Inci- 
dentally complete  records  were  kept  of  the  cost,  time, 
metal  deposited,  quality  of  electrode,  etc.  The  designs 
of  joints  were  patterned  after  those  already  suggested 
for  an  all-welded  ship  and  included  individual  designs 
of  which  there  was  doubt.  After  the  tank  was  finished 
it  was  filled  with  water  and  alternately  subjected  to  15- 
pounds  pressure  and  22-inches  vacuum.  The 'designer 
and  builder  reports  that  "  after  the  first  12  cycles  had 
been  completed,  a  break  occurred  at  one  end  of  the  box ; 
the  break  was  confined  principally  to  the  solid-end  and 
bottom  plate.  .  .  .  After  42  cycles  the  end  patch 
began  to  leak  and  had  to  be  welded  along  one  edge. 
.  .  .  After  repairs  had  been  made  the  breathing  test 
was  continued  and  has  now  been  carried  to  200  cycles. 
There  is  now  a  slight  break  on  the  patch  and  one  in  the 
centre  of  the  bottom  seam." 

It  was  suggested  that  a  riveted  tank  similar  to  this 
12-foot  box  be  built  and  tested  in  the  same  way,  but  ship- 
builders advised  that  their  experience  with  riveted  tanks 
showed  that  such  an  undertaking  was  a  waste  of  time 
and  money  in  that  no  riveted  tank  could  be  kept  water- 

^ Electric  Arc  Welding  in  Tank  Construction,"  R.  E.  Wagner,  General 
Electric  Review^  December,  1918. 


DISCUSSIONS  ON  ARC  WELDING  123 


tight  nor  stand  the  abuse  given  the  all- welded  tank.  A 
tank  of  the  same  dimensions  and  materials  has  been 
assembled  and  built  on  the  rigid  system.  This  tank  has 
not  yet  been  tested. 
^  Ductility  Versus  Strength. — Closely  connected  with 
the  discussion  on  covered  and  bare  electrodes  was  that 
of  the  results  from  these  instrumentalities.  A  good 
strength  weld  was  possible  in  mild  steel  with  the  bare 
electrode,  but  the  flux-covered  or  even  thinly-coated 
electrodes  could  produce  a  weld  with  very  much  greater 
ductility.  It  was  claimed  broadly  that  strength  welds 
were  not  all  that  was  desired  in  a  ship  joint.  The  ship 
subject  at  all  time  to  the  forces  of  waves  and  wind, 
affected  by  continual  vibration  of  her  own  propelling 
power  and  fatigued  by  the  creeping  action  of  many  com- 
plicated moments  of  forces — all  these  must  be  insured  by 
joints  that  would  bend  and  not  break;  that  would  strain 
and  not  leak ;  that  would  creep  and  not  snap  away ;  and, 
in  short,  would  act  in  all  respects  like  rubber.  Upon 
question  it  was  admitted  that  riveted  ships  hardly  ap- 
proached this  desideratum  and  that  in  practice  the  riveted 
joint  was  comparatively  a  rigid  joint.  The  suggestion 
then  followed  that  as  ductile  welds  were  expensive  for 
electrodes,  time,  etc.,  and  not  always  to  be  assured, 
strength  welds  of  85  to  90  per  cent,  of  the  plate,  or 
greater  than  the  plate  strength,  be  designed  and  em- 
ployed. To  the  practitioner  this  was  reasonable  and 
permitted  the  work  of  shipbuilding  to  proceed;  but  to 
the  theorists  such  an  argument  was  alarming,  and  they 
advised  that  the  whole  subject  of  the  application  be  re- 
turned to  the  laboratory  for  further  investigation. 

Cast  Iron. — From  time  to  time  claims  are  made  that 


124 


SPOT  AND  ARC  WELDING 


cast  iron  can  be  welded  to  cast  iron,  or  cast  iron  to  cast 
steel.  Like  many  arguments,  deductions  were  made 
from  misleading,  if  not  entirely  wrong,  premises  and 
often  the  parties  to  the  controversy  were  both  right.  In 
a  large  way  it  was  heralded  that  the  engine  cylinders  of 
the  interned  German  ships  which  were  of  cast  iron  had 
been  electrically  welded.  The  correct  statement  was 
that  they  had  been  admirably  repaired  by  the  instru- 
mentality of  the  metallic  arc  in  combination  with  me- 
chanical skill.  There  is  no  doubt  that  the  method 
employed  was  superior  both  in  point  of  economy  and 
excellence  of  result.  Briefly,  the  method  was  to  make  a 
cast-steel  patch  to  fit  the  broken  part.  A  series  of  studs 
were  tapped  into  the  cast-iron  cylinder.  From  these 
studs  metal  was  deposited  from  the  electrode  which  was 
carefully  played  about  the  seam  locally  so  as  not  to  cause 
dangerous  over-heating.  When  the  V  of  the  seam  was 
filled  the  deposited  metal  was  continued  until  it  covered 
a  broad  band.  The  finished  weld  was  then  hammered 
with  the  intention  of  improving  the  quality  of  the  weld 
as  well  as  stopping  leaks.  Samples  of  this  work  were 
examined  both  for  physical  tests  and  for  fusion  of  the 
metals.  The  weld,  as  expected,  was  always  stronger 
than  the  cast  iron  and  invariably  the  samples  broke  at 
the  joint.  A  small  piece  of  deposited  metal  on  the  cast 
iron  could  be  easily  broken  off.  This  carried  with  it  some 
of  the  cast  iron,  but  also  indicated  a  brittle  structure  at 
the  jointvire.  It  would  seem  that  the  cast  iron  was  weak- 
ened by  the  reactions  which  take  place  in  the  heat  of  the 
arc  and  the  chemical  changes  caused  by  the  constituents 
of  the  electrode  material.  From  such  large  work  as 
engine  cylinders  and  the  method  used  for  their  repair,  no 


DISCUSSIONS  ON  ARC  WELDING  U5 


reasonable  deduction  can  be  made  that  small  pieces  of 
cast  iron  can  be  arc  welded.  Fundamentally,  cast  iron 
is  a  cheap  material  with  a  rating  in  this  country  of  ap- 
proximately 17,000  to  18,000  pounds  per  square  inch 
tensile  strength.  Though  some  engineers  state  that  cast 
iron  may  be  welded  as  well  by  the  arc  as  by  any  other 
method,  they  are  quick  to  restrict  this  statement  by  the 
clause,  "  but  the  results  are  always  uncertain." 

Automatic  Arc  Welding. — In  line  with  the  prophe- 
cies that  manual  arc  welding  would  be  superseded  by 
some  form  of  machine,  one  of  this  group  of  specialists 
devoted  himself  to  the  practical  solution  of  this  problem. 
The  methods  he  pursued  and  the  present  results  which 
he  has  attained  not  only  tell  a  story  of  achievement  but 
also  reflect  much  light  of  importance  to  arc-welding 
operators.  Here  is  his  own  description  of  his  first 
assumptions  and  how  they  developed : 

"  Early  in  his  investigations,  the  writer  ^  concluded 
that  a  substantial  equilibrium  must  be  maintained  be- 
tween the  fusing  energy  of  the  arc  and  the  feeding  rate 
of  the  welding  strip ;  and  it  soon  became  evident  that  if 
the  welding  strip  is  mechanically  fed  forward  at  a  uni- 
form rate  equal  to  the  average  rate  of  consumption  with 
the  selected  arc  energy,  this  equilibrium  is  actually  main- 
tained by  the  arc  itself,  which  seems  to  have,  within  cer- 
tain circumscribed  limits,  a  compensatory  action  as 
follows :  When  the  arc  shortens,  the  resistance  decreases 
and  the  current  rises.  This  rise  in  current  causes  the 
welding  strip  to  fuse  more  rapidly  than  it  is  fed,  thereby 
causing  the  arc  to  lengthen.  Conversely,  when  the  arc 
lengthens,  the  resistance  increases,  the  current  falls,  the 


^  Harry  D,  Morton,  Secretary-Treasurer,  Automatic  Arc  Welding  Co. 


126 


SPOT  AND  ARC  WELDING 


welding  strip  is  fused  more  slowly  than  it  is  fed,  and  the 
moving  strip  restores  the  arc  to  its  normal  length.  .  .  . 
While  this  compensatory  action  of  the  arc  will  maintain 
the  necessary  equilibrium  between  the  fusing  energy  and 
the  feeding  rate  under  very  carefully-adjusted  condi- 
tions, this  takes  place  only  within  relatively  narrow 
limits.  It  was  very  apparent  that,  due  to  variations  in 
the  contour  of  the  work,  and  perhaps,  to  differences  in 
the  fusibility  or  conductivity  of  the  welding  strips  or  of 
the  work,  the  range  of  this  self -compensatory  action  of 
the  arc  was  frequently  insufficient  to  prevent  either  con- 
tacting of  the  welding  strip  with  the  work  or  a  rupture 
of  the  arc  due  to  its  becoming  too  long.  The  problem 
that  arose  was  to  devise  means  whereby  the  natm^al  self- 
compensatory  action  of  the  arc  could  be  so  greatly  accent- 
uated as  to  preclude,  within  wide  limits,  the  occurrence 
of  marked  arc  abnormalities.  There  was  ultimately 
evolved,  by  experiment,  such  a  relation  between  the  fus- 
ing energy  of  the  arc  and  the  feeding  rate  of  the  welding 
strip  as  to  give  the  desired  arc  length  under  normal  con- 
ditions; and  tendencies  towards  abnormalities  in  arc 
conditions,  no  matter  how  produced,  were  caused  to  bring 
into  operation  compensatory  means  for  automatically, 
progressively,  and  correctively  varying  this  relation  be- 
tween fusing  energy  and  feeding  rate,  such  compen- 
satory means  being  under  the  control  of  a  dominant 
characteristic  of  the  arc.  In  their  ultimate  forms,  the 
devices  for  affecting  the  control  of  the  arc  are  simple 
and  entirely  positive  in  aiCtion,  making  discrepancies 
between  fusing  energy  and  feeding  rate  self -compen- 
satory throughout  widely- varying  welding  conditions."  ^ 

^Journal  of  Amer.  Imt.  Mining  Engineers,  p.  818,  1919.  Discussion  by 
Harry  D.  Morton, 


DISCUSSIONS  ON  ARC  WELDING  127 


The  inventor  of  these  machines  has  made  many  ex- 
periments to  illustrate  the  compensatory  action  of  the 
control/'  by  using  varying  compositions  of  electrode 
material  and  work  material  as  well  as  varying  the  volt- 


FiG.  27. — Morton  semi-automatic  metallic-electrode  arc-welding  machine. 

age  supply  and  changing  the  contour  of  the  work.  He 
has  developed  two  types  of  machines  which  he  designates 
automatic  and  semi-automatic.  The  latter  appears  to  be 
a  practical  shipyard  tool,  resembling  a  portable  drill 
(Fig.  27).^ 

Many  interesting  points  have  been  observed  in  the 
operation  of  these  tools.  Those  of  a  practical  nature  are : 


128 


SPOT  AND  ARC  WELDING 


(1)  The  importance  of  the  angle  of  inchnation  of  the 
electrode  to  the  work.  "  An  annular  variation  of  5  de- 
grees will  sometimes  determine  the  difference  between 
success  and  failure.  ^.  .  .  About  15  degrees  from  the 
perpendicular  works  well  in  many  cases.  In  welding 
some  materials  the  electrode  should  drag,  that  is,  point 
toward  the  part  already  welded  rather  than  toward  the 
unwelded  parts  of  the  seam."  (2)  The  affinity  between 
electrode  materials  and  work  materials.  "  Generally 
speaking,  the  Swedish  and  Norway  iron  wires  seem  to 
produce  more  quiet  arcs  and,  possibly,  a  more  uniform 
deposition  of  electrode  material  than  do  other  wires. 
•  .  .  To  date,  no  steel  has  been  tested  on  which  appar- 
ently satisfactory  welds  could  not  be  made.  High-speed 
tungsten  steel  has  been  successfully  welded  to  cold- 
rolled  shafting,  using  Bessemer  wire  as  electrode  mate- 
rial. Ordinary  steels  varying  in  carbon  content  from 
perhaps  0.10  to  0.55  per  cent,  have  been  welded  with 
entire  success."    (3)  The  electrical-supply  variations. 

So  far,  electrode  wires  ^  inch  in  diameter  have  been 
chiefly  used  in  the  machines.  Successful  welds  have 
been  made  with  current  values  ranging  from  below  90 
to  above  200  amperes  at  impressed  voltages  of  40,  45, 
50,  55,  60,  65,  and  80.  Under  these  varying  conditions, 
the  voltage  across  the  arc  has  been  roughly  from  16  to 
22.  The  machines  have  thus  far  been  run  only  on 
direct  current."  (4)  The  short  arc.  "  While  undoubt- 
edly it  is  difficult,  if  not  impossible,  to  maintain  in  manual 
welding  an  arc  shorter  than  this  (0.1  inch),  the  writer 
has  frequently,  with  the  automatic  machines,  made  con- 
tinuous and  strikingly  good  welds  with  arcs  of  much 
less  length."    (5)  Rate  of  doing  work.  "  With  the  auto- 


DISCUSSIONS  ON  ARC  WELDING  129 

matic  machine,  black  drawing  steel  0.109  inches  thick  has 
been  welded  at  the  rate  of  22  inches  per  minute.  A  De- 
troit manufacturer  welded  manually  with  oxy-acetylene 
at  the  rate  of  four  per  hour  a  large  number  of  mine  floats 
10  inches  in  diameter,  made  of  this  material.   The  auto- 


FiG.  28. — Gauge  steel  tubing  automatically  arc  welded  at  the  rate  of  1  ft.  per  minute. 

matic  machines  made  the  welds  at  the  rate  of  forty  per 
hour.  .  .  .  The  productive  capacity  of  the  machines 
so  far  made  has  been  from  three  to  ten  times  that  of 
manual  welding  methods."  (6)  Type  of  electrode. 
"  Bare  wire  only  has  been  used  in  the  automatic  ma- 
chines, and  the  results  obtained  seemed  to  indicate  that 
the  covering  of  the  electrodes  is  an  expensive  superflu- 
ity."   (7)  Cleanliness  of  materials.    "  The  writer  has 

9 


130 


SPOT  AND  ARC  WELDING 


repeatedly  welded  with  wire  showing  evidence  of  pipes 
and  seams,  as  well  as  with  rusty  wire  and  with  wire 
covered  with  dirt  and  grease.  In  this  connection  it  may 
be  said  that  no  pains  are  ever  taken  to  remove  rust,  scale 
or  slag  from  the  work  material — even  where  welds  are 
superimposed.  Apparently  under  uniform  conditions 
of  work  traverse,  arc  length  and  electrode  angle  of  in- 
clination, such  as  are  possible  in  the  automatic  machine, 


Fig.  29. — Two  3^"  ship  plates  automatically  arc  welded. 

impurities  vanish  before  the  portion  of  the  work  on  which 
they  occur  reaches  the  welding  area  of  the  arc." 

Many  of  these  practical  observations  of  automatic 
arc  welding  will  change  former  opinion,  but  their  great- 
est good  will  result  in  the  attention  given  them  by  manual 
arc  welders.  In  experimenting  with  such  machines  it 
has  been  discovered  that  great  differences  in  the  welding 
results  come  about  from  the  location  of  the  ground  con- 
nection in  relation  to  the  location  of  the  arc.  Doubtless 
this  is  a  phenomenon  of  magnetism  or  conductivity.  It 
is  well  that  the  arc- welding  operator  be  acquainted  with 
such  an  observation,  although  in  large  work,  long  seams. 


DISCUSSIONS  ON  ARC  WELDING  131 


or  heavy  materials  this  phenomenon  may  not  seriously 
affect  the  goodness  of  the  weld.  Besides  these  practical 
observations  the  inventor  of  automatic  arc-welding  ma- 
chines takes  note  of  the  theoretical  side  of  the  "  con- 
trolled "  arc  which  will  be  considered  in  connection  with 
the  theories  of  electric  welding. 

The  Training  of  Operators. — Unanimity  of  opinion 
places  the  arc- welding  operator  as  the  chief  factor  of  the 
making  of  a  sound  and  perfect  weld.  His  participation 
in  the  process  has  been  estimated  at  80  to  90  per  cent. 
Early  in  the  debate  the  statement  was  made  that  the 
apparatus,  the  electrode,  or  the  work  materials  had  little 
to  do  with  a  successful  weld  when  compared  with  the 
man  who  makes  it.  The  operator  who  could  not  make  a 
weld  despite  the  opposition  of  these  elements  was,  at 
least,  not  a  skilled  welder.  This  does  not  mean  that 
there  were  not  combinations  that  could  for  a  time 
baffle  his  skill,  but  it  does  mean  that  the  skilled  welder 
if  not  interfered  with  could  produce  excellent  work 
without  specialized  apparatus  or  with  elaborately 
prepared  electrodes. 

This  was  not  the  essential  question.  The  timidity  of 
conservative  advocates  of  arc  welding  was  occasioned  by 
this  very  high  percentage  of  operator  and  the  inconsist- 
ent results  of  his  work.  In  other  words,  the  conserva- 
tives were  not  willing  to  risk  their  reputation  because  of 
the  non-uniformity  and  instability  of  this  personal  equa- 
tion. It  is  nonsense  to  say  that  the  operator  could  not 
hide  poor  work,  for  this  he  could  do  and  more — he  could 
place  good  and  bad  work  side  by  side.  For  this  reason 
the  first  requirement  claimed  for  the  operator  was  that 
he  be  conscientious. 

On  the  other  hand,  the  radicals  adhered  to  their  prac- 


132 


SPOT  AND  ARC  WELDING 


tical  view  that  men  who  had  some  knowledge  of  steel 
jointure  either  in  blacksmith  shops  or  boiler  shops  could 
be  made  good  welders.  The  work  of  such  had  been  in 
use  for  many  years  for  much  serious  work,  and  this  was 
a  sufficient  guarantee  of  the  results.  They  pointed  to 
other  long-tried  methods  and  asked  why  demands  were 
not  made  to  destroy  such  work,  as  it  too  only  received 
exterior  inspection.  For  example,  the  large  varied  use 
of  cast  iron  for  many  purposes  connected  with  danger 
to  life,  so  steel  castings  and  forgings:  who  knew  what 
was  inside  of  these  finished  articles?  It  was  not  that  they 
did  not  agree  with  the  conservatives  that  for  special 
work  a  competent  man  should  be  employed,  but  that 
there  was  too  much  stress  laid  on  the  importance  of  the 
operator  for  a  large  run  of  work. 

In  the  eagerness  of  the  desired  application  it  was 
natural  that  the  time  of  training  welders  should  be  given 
most  attention.  There  were  engineers  who  did  not  hesi- 
tate to  state  that  arc  welders  could  be  trained  in  a  few 
days.  A  little  experience  on  the  part  of  any  one  with 
the  handling  of  the  electrode  would  assure  that  this  time 
was  too  short.  Any  one  with  a  steady  hand  and  a  com- 
fortable adjustment  of  the  electrical  supply  may  make 
the  first  time  a  deposit  of  metal  from  the  electrode;  but 
he  makes  a  great  error  if  he  leads  himself  to  believe  that 
this  is  all  that  is  required  to  produce  uniformly  good 
welds.  As  previously  noted  there  is  a  great  difference 
in  the  training  of  a  man  for  one  single  operation  and 
making  the  same  man  capable  of  applying  his  knowledge 
and  training  to  a  large  variety  of  work. 

Further  details  of  the  training  of  operators  will  be 
treated  in  the  next  chapter. 

Summary. — The  endeavor  of  this  chapter  has  been 


DISCUSSIONS  ON  ARC  WELDING 


133 


to  rehearse  briefly  the  salient  discussions  on  arc  welding 
and  its  bearing  on  the  application  to  the  industries. 
Questions  here  alluded  to  have  been  selected  for  their 
interest  to  the  general  practitioner  and  to  illustrate  the 
many-sided  nature  of  the  opinions.  The  following  list 
gives  an  idea  of  the  investigations  suggested : 

The  supply  and  distribution  of  electric  power. 

Vanadium  coating  on  electrodes. 

Titanium  coating  on  electrodes. 

Boron  sub-oxide  coating  on  electrodes. 

Magnesium  coating  on  electrodes. 

Titanium-core  electrodes. 

Boron-core  electrodes. 

Charcoal-core  electrodes. 

Aluminum-core  electrodes. 

The  effect  of  the  height  of  deposited  metal  in  weld. 

The  value  of  extending  the  projection  of  the  de- 
posited metal  in  the  weld. 

Determination  of  the  separation  distance  between  the 
metals  to  be  joined. 

The  proper  size  of  lap  in  a  lap-joint. 

The  proper  width  of  strap  in  a  butt-strap  design. 

The  proper  thickness  of  strap  for  varying  thicknesses 
of  plate. 

The  advantages  of  change  of  current  for  different 
layers  of  deposited  metal. 

The  effects  of  increased  current  on  different  sizes 
of  electrode. 

The  limits  of  layers,  i.e.,  how  many  for  varying  thick- 
nesses of  steel  plating. 

Effects  of  the  elements,  i.e.,  rain,  wind,  snow,  etc. 
Eye  protection  for  the  operator. 


CHAPTER  VII 


The  Arc  Welder 

If  successful  arc  welds  are  dependent  upon  the  man 
behind  the  electrode  it  is  fair  to  assert  that  those  who 
wish  the  best  of  this  process  should  consider  him  care- 
fully. Experience  in  the  training  of  miscellaneous  men 
has  shown  that  no  amount  of  training  will  make  a  man  a 
welder.  Some  men  are  so  constituted,  or  have  been  so 
molded  by  other  occupations,  that  they  cannot  hope  to 
acquire  skill  in  the  handling  of  the  electrode.  Electric 
welding  is  in  this  respect  no  different  from  any  of  the 
other  vocations  and  has  its  degrees  expressed  by  the 
competency  of  the  man.  This  comparative  scale  does 
not  mean  exclusion,  but  for  special  apphcations  it  signi- 
fies the  importance  of  selection.  To  the  employer 
undoubtedly  all  degrees  of  proficiency  will  have  their 
field  of  usefulness  and  the  lower  degrees  will  work  up- 
ward through  the  fostering  of  ambition.  This  is  the 
keynote  of  selection.  An  experience  with  metals,  a  prac- 
tical knowledge  of  the  effects  of  heat  treatment,  even  a 
few  years'  use  of  the  electrode  in  repair  work — all  these 
may  aid  the  arc  welder  in  seeking  a  job,  but  they  will 
not  assure  the  employer  that,  even  with  months  of  train- 
ing, the  man  will  be  a  welder  upon  whom  he  may  rest 
the  responsibility  of  a  new  application.  On  the  other 
hand,  a  man  who  knows  nothing  of  these  things  but  who 
displays  a  spirit  of  conquest  and  a  willingness  to  accept 
failure  that  he  may  gain  success,  this  fellow  will  make 
not  "  just  a  welder,"  but  a  skilled  craftsman. 

134 


THE  ARC  WELDER 


135 


Training. — Forced  methods  are  not  conducive  to  the 
best  results.  Some  men  can  right  themselves  under  the 
confusion  of  haste,  but  others  cannot  get  their  bearings. 
The  object  of  the  Emergency  Fleet  Corporation  was  to 
aid  the  shipbuilders  in  hastening  the  construction  of 
ships.  The  procedure  adopted  was  a  notification  to  the 
shipbuilders  that  training  would  be  furnished  to  such 
men  as  they  cared  to  select  with  the  option  of  welding 
instruction,  and  in  addition,  an  intensive  course  in  prac- 
tical methods  of  imparting  knowledge.  This  latter  gave 
the  shipbuilder  the  opportunity  of  setting  up  his  own 
training  school  after  a  few  men  were  equipped.  Upon 
the  introduction  of  this  system  a  restricted  bonus  was 
offered  to  those  who  immediately  accepted  the  proposal. 
This  arrangement  reacted  advantageously  to  the  train- 
ing, as  it  permitted  the  retention  of  the  men  in  the 
schools  until  they  were  proficient  with  the  electrode.  By 
making  the  training  exclusively  for  the  shipbuilding  in- 
dustry another  constant  was  established,  namely,  the 
Work  material.  In  this  respect  the  training  of  arc 
welders  was  a  specialty.  Although  a  broad  view  was 
taken  of  the  benefits  of  a  liberal  education,  this  feeling 
was  held  in  check  by  the  demand  for  men  who  could  be 
trusted  to  weld  certain  parts  of  the  ship  without  endan- 
gering the  structure  or  discounting  the  advantages  of 
the  process. 

Another  constant  could  have  been  instituted  but 
opinions  pointed  to  the  necessity  of  future  development. 
This  refers  to  the  question  of  the  kind  of  electrode. 
Guided  by  American  practice  the  bare  mild  steel  elec- 
trode could  have  been  made  the  standard  and  the  men 
trained  only  with  this  type ;  but  persuaded  by  argument 


136 


SPOT  AND  ARC  WELDING 


and  the  examples  of  what  had  been  done  in  England 
the  men  were  also  trained  with  the  covered  electrode. 
That  in  practice  this  policy  did  not  warrant  the  exertions 
made,  nothing  can  be  said,  as  the  application  has  not  yet 
been  put  to  the  full  test  of  shipbuilding  in  this  country. 
It  cannot  be  known  whether  the  first  welded  ship  will  be 
built  with  either  one  or  the  other  type  of  electrodes,  but 
very  likely  both  would  be  used. 

Endeavors  were  made  to  provide  at  every  school 
various  types  of  apparatus  so  that  the  student  would  be 
familiar  with  the  special  features  and  characteristics  of 
operation  of  different  machines.  This  was  done  for  two 
reasons:  (1)  That  no  question  of  commercial  preference 
could  be  raised,  and  (2)  that  the  men  would  be  prepared 
to  operate  any  apparatus  in  the  event  that  their  company 
wished  to  experiment  with  a  number  of  types.  Although 
it  has  been  stated  that  arc  welders  did  not  need  to  know 
anything  about  electricity,  the  intention  being  the  science 
of  electricity,  it  is  of  importance  for  him  to  be  able  not 
only  to  start  his  motor  generator  and  adjust  the  current 
for  welding,  but  also  to  understand  enough  of  the  work- 
ings of  the  machinery  to  exercise  discrimination  in  the 
case  of  derangement  of  the  apparatus.  In  some  of  the 
schools  the  equipment  was  not  so  diversified  as  it  should 
have  been,  with  the  result  that  a  number  of  men,  although 
well  equipped  as  welders,  did  not  obtain  a  proportionate 
knowledge  of  arc-welding  machinery.  This  is  a  handi- 
cap for  good  welding,  as  many  of  the  manufacturers  do 
not  agree  in  their  fundamentals  of  design  with  this  result 
to  the  welding  operator  that  frequently  he  will  make 
adjustments  on  a  machine  that  will  not  produce  the 
desired  results  because  of  his  lack  of  familiarity  with 


THE  ARC  WELDER 


137 


this  particular  apparatus.  The  Emergency  Fleet  Cor- 
poration was  able  to  give  this  additional  training  on 
many  different  machines  through  the  courtesy  of  various 
manufacturers  throughout  the  country. 

For  the  purposes  of  standardization  a  list  of  symbols 
was  proposed  and  approved.  This  list  has  been  adopted 
as  a  standard  by  all  users  of  the  process  throughout  this 
country.  It  led,  as  will  be  seen  from  the  last  page,  to  the 
important  economic  point  of  the  simplification  of  detail 
drawings.  Those  familiar  with  riveted  structures  appre- 
ciate the  necessity  of  calculations,  allowances  of  spacing 
of  rivets,  and  dimensioning  of  such  drawings.  Here 
was  a  uniform  set  of  standard  symbols  which,  when 
understood  by  the  arc  welder,  were  placed  on  an  outline 
drawing  and  then  sent  to  the  yard.  These  symbols  were 
purposely  made  elaborate  so  that  the  entire  ground 
would  be  covered,  but  it  was  intended  to  simplify  them 
as  the  application  settled  into  established  practice.  The 
men  under  training  were  all  drilled  in  the  symbols  as 
here  given,  as  will  be  noted  on  the  sample  record  of  the 
student  (Fig.  30). 

In  view  of  the  fact  that  this  training  was  special,  a 
detail  of  each  practice  lesson  would  be  of  little  value.  A 
good  general  course  of  lessons  for  commercial  welding 
will  be  found  in  the  Appendix.  As  a  matter  of  fact,  time 
did  not  permit  the  establishment  of  standard  methods  of 
instruction  throughout  the  schools.  The  procedure  of 
the  training  may  be  of  interest. 

First,  the  student  was  provided  with  such  necessaries 
as  gloves,  screens,  electrode  holder,  etc.,  and  then 
assigned  to  a  welding  booth.  He  was  then  shown  by  the 
instructors  how  to  hold  his  electrode,  both  at  the  proper 


StOT  AND  ARC  WELDING 


THE  ARC  WELDER 


139 


angle  and  the  correct  distance  from  the  work.  He  was 
then  allowed  to  practice  on  depositing  one  layer  of  metal 
in  rows  on  a  flat  plate.  Following  this  he  placed  a  second 
layer,  then  a  single  layer  between  the  first  row  and  then 
completing  the  sample  by  a  second  layer.  The  sample 
was  then  to  be  retained  by  the  instructor  as  a  record  and 
inspected  for  the  determination  of  rating.  This  same 
exercise  was  repeated  with  the  work  material  set  up  at 
an  angle  of  45  degrees  from  the  welding  table.  Follow- 
ing this  practice  the  same  exercises  were  carried  out 
in  the  vertical,  horizontal,  and  overhead  positions. 
The  first  course  was  done  entirely  with  the  bare  mild 
steel  electrode.  They  were  repeated  with  the  slag- 
covered  electrode. 

It  was  expected  by  the  time  the  student  had  per- 
formed these  exercises  he  would  gain  sufficient  confi- 
dence in  his  ability  to  undertake  the  more  difficult 
joining  of  plates.  If  in  the  judgment  of  the  instructor 
his  deposited  samples  did  not  give  evidence  of  such  con- 
fidence he  would  repeat  such  of  the  exercises  as  he  consid- 
ered adequate.  The  student  was  then  given  a  graded 
course  in  joining  small  samples  of  ^-inch  steel  plate 
with  different  types  of  joints  in  all  positions.  These 
exercises  were  repeated  with  i/2-inch  plate.  In  the  same 
way  as  with  the  deposited  metal  sample,  first  the  sample 
joints  were  made  with  the  bare  electrode  and  then  with 
the  covered.  Coupled  with  these  exercises  and  in  some 
cases  interrupting  the  regular  course,  production  jobs 
were  given  the  more  proficient  student.  Although 
in  a  way  these  exercises  were  laid  out  as  routine  les- 
sons the  exigencies  of  the  training  were  such  that 
it  was  considered  beneficial  not  to  make  the  instruction 
too  monotonous. 


140 


SPOT  AND  ARC  WELDING 


The  time  of  the  student  in  the  schools  was  never 
limited.  If  the  man  were  conscientious,  speed  was  not  a 
consideration,  but  the  quality  of  his  work  permitted  his 
discharge  that  much  sooner.  As  a  matter  of  general 
interest  the  average  time  of  the  average  student  in  be- 
coming proficient  in  the  handling  of  the  electrode  was 
approximately  eight  weeks.  That  is  to  say,  that  by  con- 
sistent attention  the  average  student  could  go  through 
the  course  laid  down  in  this  time.  There  were  some  men 
in  attendance  for  three  months.  There  were  others  who 
finished  the  course  in  five  or  six  weeks. 

Home-office  records  were  kept  of  the  available  arc 
welders  in  order  to  supply  information  of  this  kind  to 
the  shipbuilders.  The  form  for  this  purpose  is  shown  in 
Fig.  31.  From  this  accumulated  data  a  list  was  com- 
piled filing  additional  information  that  would  both  aid 
in  the  proper  selection  of  men  and  would  assist  the  in- 
structor in  case  any  of  the  men  were  sent  to  one  of  the 
training  schools.  Following  this  system  a  card  was  filed 
(Fig.  32)  for  each  student.  On  this  card  the  designa- 
tions of  the  different  schools  (called  training  centres) 
are  given  and  space  is  provided  for  showing  transfers 
from  one  school  to  another.  The  shifting  of  the  student 
was  not  the  usual  procedure,  although  in  some  cases  it 
was  deemed  advisable.  At  times  better  instruction  was 
given  in  certain  details  in  one  school  than  at  another, 
physical  opportunities  sometimes  decided  the  transfer, 
and  rarely  the  transfer  was  requested  by  the  employer. 
Although  this  filing  card  shows  seven  welding  schools, 
the  work  never  proceeded  to  more  than  five  schools,  as 
follows:  One  in  Schenectady,  N.  Y. ;  one  in  Cleveland, 
Ohio;  one  in  Brooklyn,  N.  Y. ;  one  in  San  Francisco, 


THE  ARC  WELDER 


141 


n 

o 


B 
5" 

n  ■ 


o 
o 

I— I 


c 


o 


o 
c 


p 

O 


3 


o 
cr 
0 


CfQ 


> 


O 


P 


o 


p 

3 


3 

1^ 


p 
3 


5  o 
•  3 


W 
O 

W 

I— ( 


o 


o 


142 


SPOT  AND  ARC  WELDING 


Cal. ;  and  one  in  Philadelphia,  Pa.  The  two  latter  schools 
were  only  just  opened  when  the  electric- welding  activi- 
ties of  the  Emergency  Fleet  Corporation  ceased.  In 
conjunction  with  the  home-office  record  of  the  students, 
a  weekly  report  was  forwarded  from  each  head  instructor 
of  the  schools  (Fig.  30).  As  will  be  seen,  this  report 
was  filled  in  by  the  student  up  to  the  column  headed 
actual  welding  time,"  from  this  column  it  was  filled  in 
by  the  instructor.  It  will  be  noted  that  the  standard 
list  of  symbols  is  used  with  slight  modifications  due  to 
the  fact  that  the  students  were  not  working  from  draw- 
ings, so  that  drawing  symbols  would  only  confuse  them. 
These  weekly  reports  gave  a  check  on  the  instructor  as 
well  as  the  student,  and  also  formed  a  reference  in  deter- 
mining the  results  of  the  examinations  for  certification. 

It  was  determined  to  certificate  those  men  who  after 
several  months'  actual  work  in  the  shipyards  showed 
themselves  capable  of  performing  successfully  with  the 
electrode.  This  required  a  further  examination  of  the 
student.  The  system,  though  exacting  fairly  rigid  re- 
quirements, was  based  on  broad,  practical  lines  following 
the  course  of  instruction  given.  As  a  guide  for  deter- 
mining whether  the  man  was  entitled  to  certification 
these  points  of  observation  were  required  of  the  examin- 
ing instructor :  ( 1 )  Ability  to  weld  in  all  positions,  flat, 
horizontal,  vertical,  and  overhead.  (2)  Ability  to  weld 
in  all  positions  with  both  alternating  and  direct  current. 
(3)  Ability  to  weld  in  all  positions  with  both  bare  and 
covered  electrodes.  (4)  Ability  to  maintain  an  arc  not 
over  ys  inch  long,  without  more  than  three  breaks  in  a 
12-inch  run  of  the  electrode.  (5)  Welding  by  observa- 
tion must  be  smooth  and  even.    (6)  A  sample  weld  when 


THE 


ARC  WELDER 


143 


B 


CJ5 


B 

cr 


p 


p 


o  o 


CfQ 


P 


p 


p 


o 

o 

•ucl 

o 

o 

en 

o 

9. 

)mpl 

itry 

's  CO 

)mpl 

itry. 

)  mpletion. 

eti( 

w 

CP 
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<^ 
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0 

p 


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B 


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CfQ 


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ft* 
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?! 

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^   ^  ^ 


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a. 


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144 


SPOT  AND  ARC  WELDING 


cut  by  hack  saw  must  show  perfect  penetration  with 
work  materials.  (7)  The  weld  must  be  free  from  slag 
and  blow  holes.  (8)  The  operator  must  display  a  knowl- 
edge of  the  effects  of  too  high  or  too  low  open  voltage. 
(9)  The  operator  must  display  a  knowledge  of  the  cor- 
rect current  adjustment  for  the  electrode  size  and  work 
material.  ( 10)  The  operator  must  display  a  knowledge 
of  the  proper  polarity  for  various  welding  conditions. 
(11)  The  operator  must  not  be  examined  unless  he  has 
had  at  least  four  months'  experience  in  production  work. 

Differing  slightly  from  these  requirements  for  cer- 
tification the  following  points  were  laid  down  as  a  guide 
to  the  examining  instructor  for  a  refusal  to  recommend 
certification:  (1)  Unsteady  habits  of  the  operator.  (2) 
Inability  to  hold  an  arc  ^  inch  or  less.  (3)  Slag  or 
blow  holes  found  in  the  welded  sample.  (4)  A  rough  or 
uneven  weld.  (5)  Lack  of  penetration  when  the  welded 
sample  is  cut  with  hack  saw.  (6)  When  the  sectional 
area  of  the  weld  is  equal  to  the  sectional  area  of  the  work 
material,  the  ultimate  tensile  strength  of  the  weld  must 
not  be  less  than  75  per  cent,  of  the  work  material.  (7) 
Lack  of  knowledge  of  current  adjustment,  size  of  elec- 
trode, kind  of  electrode,  and  voltage  conditions.  (8) 
Lack  of  knowledge  as  to  the  proper  polarity  for  the 
type  of  weld.  (9)  Less  than  four  months'  experience 
in  production  work. 

With  these  instructions  the  examiner  was  sent  to  the 
plant  employing  the  student  and  made  his  notations  on 
a  record  card  (Fig.  33).  These  cards  were  kept  on  file 
as  a  reference  when  viewing  the  sample  welds.  These 
latter  were  brought  to  headquarters  for  final  examina- 
tion and  tests.   The  system  was  planned  to  avoid'  inter- 


THE  ARC  WELDER 


X 

B 

B' 

p 

O* 

3 


o 

O 

o 

p 

00 

o 

p 


5^ 
n 


No. 

No. 

No. 

No. 

00 

p 

O 

o 

c 

Of 

00 

h- 1 

No. 

No. 

No. 

No. 

GO 

to 

o 
p 

B 


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n 

o 

C3 


oo<?o:iCriyf^ooi©i-' 


X  y  <  <1  o  o 


CD 


tr  tr     ^.  Q  Q  p  p 

p  P  ^  P  ^  ^ 
p-  O-     —  p  p 


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CfQ 


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o 

b: 

s 


10 


146 


SPOT  AND  ARC  WELDING 


ference  with  the  operator  and,  in  addition,  to  furnish  him 
with  further  instruction  if  he  so  desired.  Fig.  34  illus- 
trates the  form  of  certificate. 

Needs  of  the  Operator. — The  process  is  not  danger- 
ous. Low  voltages  are  employed  so  that  there  is  no  fear 
of  serious  electric  shock.    The  temperature  of  the  arc  is 


Certificate  No. 


©lis  that 
(Jaursp  of  ©lurang  as  anSlfrtrir  Arc 


?kmth 


m thf      dag 0f  CTn^i's^  

^^^^  z^-aA^   


Fig.  34. — Form  of  certificate  for  arc  welder,  Emergency  Fleet  Corporation  Schools, 

high  and  the  metal  in  the  vicinity  of  the  weld  becomes 
and  remains  hot  for  some  time  after  the  weld  is  made 
and  should  be  handled  either  with  some  form  of  tongs 
or  with  non-inflammable  gloves.  The  arc  is  usually  ac- 
companied with  sputter ings  and  sparking  which  requires 
that  the  operator  wear  gauntlets  so  that  the  spark  will 
not  burn  his  arms.  It  is  not  the  general  custom  to  wear 
a  leather  apron,  though  in  some  positions  and  classes  of 


THE  ARC  WELDER 


147 


work  this  should  be  insisted  upon.  Usually  the  arc 
welder  wears  a  pair  of  overalls,  but  if  a  piece  of  slag 
accidentally  falls  or  is  blown  from  his  weld  his  overalls 
will  not  protect  him.  Accidents  have  been  caused  by 
molten  metal  falling  into  the  shoe- top,  and  it  is  wise  to 
provide  shoes  with  special  tongues. 

The  most  necessary  protection  is  that  for  the  eyes. 
Many  investigations  ^  have  been  undertaken  in  order  to 
supply  the  operator  not  only  with  correct  lenses  in  the 
sense  of  preventing  the  harmful  invisible  rays,  but  also 
with  proper  lenses  that  will  not  reduce  the  light  intensity 
so  low  that  vision  is  difficult.  The  arc  welder  must  see 
as  much  as  possible  what  is  going  on  while  the  electrode 
is  depositing  metal  in  the  weld.  Protective  lenses  may 
be  mounted  in  three  ways.  For  inspection  work  a  pair 
of  close-fitting  goggles  is  all  that  is  necessary.  They 
must  be  screened  at  the  sides,  because  the  invisible  viltra- 
violet  and  infra-red  rays  are  reflected  in  the  same  way  as 
visible  rays.  Goggles  do  not  protect  the  operator  as 
well  as  a  hand  screen.  He  can  quickly  lay  this  down 
when  he  has  broken  his  arc  and  it  gives  him  a  ready 
means  for  viewing  quickly  his  cooling  metal.  The  screen 
covers  his  face  and  chest,  giving  him  protection  on  all 
sides.  Some  operators  claim  a  liking  for  the  screen  on 
the  basis  of  its  steadying  quality ;  that  is,  by  holding  the 
left  arm  tightly  pressed  to  the  body  gives  added  confi- 
dence to  the  movements  of  the  right  arm.  Metallic  arc 
welders  rarely  use  a  helmet,  but  in  carbon  arc  welding 
this  is  necessary  both  for  the  added  protection  to  the 

^  "  Eye  Protection  in  Iron-Welding  Operations,"  W.  S.  Andrews,  General 
Electric  Review,  December,  1918;  Bulletin  93,  Technologic  Papers,  Bureau 
of  Standards,  Washington,  D.  C. 


148 


SPOT  AND  ARC  WELDING 


neck  and  shoulders  from  the  intense  heat,  and  also  for 
the  freedom  of  the  left  hand,  in  which  the  melt  rod  must 
be  manipulated.  There  are  many  designs  of  helmets 
and  screens  which  are  subject  to  the  personal  preference 
of  the  welder.  In  some  welding  shops  combination  of 
glasses  for  making  up  lenses  are  left  to  the  selection  of 
the  operator.  Only  glasses  are  provided  whose  combina- 
tions will  guarantee  safety.  Other  employers  are  more 
rigid  and  require  only  one  type  of  glass  to  be  used.  A 
clear  glass  is  placed  outside  of  the  colored  lenses  to  pro- 
tect them  against  pitting.  The  cheap  clear  glass  saves 
the  expensive  colored  glass. 

Three  Important  Lessons. — Too  much  stress  can- 
not be  laid  upon  the  primary  points  in  the  instruction  of 
an  electric  welder.  All  training  practice  must  begin 
with  the  laying-on  of  metal  from  the  electrode.  The 
three  following  lessons  explain  clearly  how  the  beginner 
should  practice  in  (1)  making  beads,  (2)  spreading  the 
deposited  metal,  and  (3)  padding. 

"  Lesson  I 
"beads 

"  As  shown  in  Fig.  35,  Lesson  I,  Running  Beads. 
The  electrode  must  be  held  close  to  the  work,  ix.j, 
a  close  arc  for  successful  welding.  The  natural  ten- 
dency is  to  draw  a  long  arc,  but  in  this  case  too  much  of 
the  heat  is  lost  by  air  radiation  and  there  is  too  great  an 
area  for  oxidation  of  the  metal  in  passing  from  the  elec- 
trode to  the  work  and  there  is  too  gi^eat  an  area  provided 
for  the  air  to  get  in  and  form  oxide  and  nitride,  both  of 
which  are  very  undesirable  impurities  in  the  weld.  There 


BEADS 


149 


is  a  further  chance  with  a  long  arc  that  the  electrode 
material  will  not  be  deposited  in  the  parent  metal  made 
fluid  by  the  arc,  but  spattered  outside  or  overlapping,  in 
which  case  no  weld  results. 

As  shown,  the  electrode  material  must  pass  into  the 
crater  or  fluid  bowl  of  the  work  made  so  by  the  arc,  and 
the  electrode  must  be  held  in  such  a  position  that  the 
metal  can  pass  nowhere  but  into  this  fluid  bowl. 

The  fluid  bowl  only  appears  at  the  point  the  arc 
strikes,  and  the  arc  must  be  kept  striking  just  ahead  of 
the  deposited  metal  partially  in  the  parent  metal  or,  to 
say  it  in  another  way,  the  arc  must  be  kept  at  the  advanc- 
ing edge  of  the  puddle.  If  the  arc  is  allowed  to  draw 
back  on  the  bead  simply  a  bridge  of  metal  welded  from 
the  weld  to  the  point  where  the  arc  next  strikes  the  par- 
ent metal  will  result.  This  exercise  should  be  made  with 
both  flux-coated  wire  and  bare  wire.  It  will  be  noted 
that  with  flux-coated  wire  with  the  bare  side  advancing 
as  it  is  designed,  the  flux  coating  will  follow  along, 
covering  the  molten  puddle  and  preventing  the  arc  back- 
ing up  on  the  weld  providing  a  close  arc  is  held. 

To  get  the  correct  rate  of  heat  for  any  given  condi- 
tion of  electrodes  or  work  the  following  test  should  be 
applied,  and  it  is  the  best,  in  fact,  the  only  test  yet  de- 
vised. Run  a  bead  and  note  whether  the  edges  are 
undercut  as  at  Fig.  35b,  overlapped  as  at  Fig.  35c,  or 
perfect  as  at  Fig.  35d.  If  they  are  slightly  undercut  it 
can  be  told  by  looking  at  the  bead,  but  the  perfect  weld 
and  the  overlapped  weld  can  only  be  told  by  chipping 
off  the  beads.  Different  electrodes  melt  at  different 
rates  of  heat,  and  different  kinds  of  parent  metal  show 
small  and  large  fluid  bowls  or  craters,  depending  on  their 


150 


SPOT  AND  ARC  WELDING 


make-up,  so  that  even  with  the  correct  length  of  arc  this 
test  should  be  applied  for  each  new  condition.  The 


UNDERCUT  OVER  LAPPED  SATISFACTORY 


AIR  RADIATION 
-h  OXIDIZATION 


CRATER,  SMALL,  AND  NOT  WHERE 
METAL  DEPOSITS 


RESULTS  OF  LONG  ARC 
EXCESSIVE  OVERLAPPING  LAST  DROPS 


(f)  (9) 

Fig.  35. — Running  beads. 

undercut  in  general  results  from  a  larger  bowl  than  the 
electrode  deposited  to  fill  it,  and  the  overlapped  bead 


BEADS 


151 


may  result  from  this  or  from  a  long  arc.  Where  the 
bowl  is  made  smaller  with  an  arc  over  ^  inch  long  with 
certain  current  densities  the  bowl  may  disappear  en- 
tirely, showing  results  as  at  Fig.  35/,  g,  and  e,  which 
also  show  how  the  results  shown  may  be  had. 

"  The  bead  should  be  run  until  proficient  with  the 
three  main  different  styles  of  electrodes,  that  is,  the  com- 
pletely coated  electrode  in  which  the  arc  exists  inside  of 
a  viscous  tube  deposited  at  the  same  rate  as  the  electrode, 
the  idea  being  to  keep  the  oxygen  and  nitrogen  of  the  air 
from  combining  with  the  steel  when  molten  and  when  it 
has  its  greatest  chemical  affinity.  With  this  electrode  a 
slag  is  left  around  and  on  top  of  the  weld  which  must 
be  chipped  off  for  a  clean  start  if  the  arc  should  happen 
to  get  out  or  in  restarting  to  continue  the  bead. 

"  With  the  flux-covered  electrode,  bare  side  advanc- 
ing, it  will  be  noted  that  there  is  no  danger  of  slag  inclu- 
sion and  that  the  slag  can  be  crushed  off  and  that  in 
restarting  there  is  no  need  for  chipping  the  weld  clean. 
The  best  way  of  cleaning  the  weld  is  by  the  same  action 
which  brings  the  slag  and  dross  to  the  surface  of  the 
weld  with  this  electrode.  With  bare  wire  there  is  natur- 
ally no  danger  of  slag  inclusion,  but  a  continuous  amount 
of  the  oxide  and  nitride  of  iron  are  included  as  the  time 
for  bringing  them  to  the  surface,  i.e.,  while  the  metal  is 
too  short  to  allow  them  to  disentangle  and  come  to 
the  surface. 

"  After  proficiency  in  running  beads  horizontally  is 
attained  the  beads  should  be  run  on  a  vertical  surface 
from  the  bottom  up.  Here  it  will  be  noted  a  close  arc 
must  be  held  or  metal  will  run  away.  The  next  step  is 
to  run  the  beads  horizontally  on  the  vertical  surface,  and 


152 


SPOT  AND  ARC  WELDING 


lastly,  from  the  top  down.  By  this  time  a  close  arc  will 
be  so  natural  that  overhead  welding  can  be  attempted, 
but  if  not  successful  no  worry  need  result,  as  it  will  come 
naturally  in  time.  The  most  important  things  to  be 
learned  in  running  beads  are :  ( 1 )  Close  arc,  i.e.,  not  so 
close  as  to  sputter,  but  close  enough  to  crackle.  (2) 
Keep  the  arc  at  the  advancing  edge  of  the  puddle.  Beads 
are  used  commercially  to  seal  cracks,  caulking  edges, 
and  as  the  first  layer  in  butt  and  fillet  welding 
for  ductility. 

"  Lesson  II 
"spreading 

"  Here  the  electrode  method  is  applied  by  moving  the 
electrode  from  side  to  side  at  the  same  time  advancing, 
i.e.,  back  and  forth  in  a  zig-zag  manner  as  show^n  in  Fig. 
36a.  The  electrode  must  not  be  moved  rapidly,  i.e., 
must  not  be  moved  faster  than  the  arc  can  make  the 
liquid  bowl  or  crater  and  must  be  moved  at  an  even  rate, 
so  that  this  crater  becomes  a  trough  into  which  the  elec- 
trode material  is  deposited  at  an  even  rate.  The  rate  of 
speed  back  and  forth  of  the  electrode  must  be  the  same 
rate  as  that  used  for  the  advance  in  running  beads,  and, 
in  fact,  each  successive  layer  in  spreading  is  simply  cross- 
wise beading  done  continuously  and  shortly,  the  welded 
metal  becomes  heated  to  such  a  point  where  a  greater 
speed  is  attainable  than  at  first.  It  will  be  noted  that 
the  completely-covered  slag-coated  electrode  lends  itself 
admirably  to  this  method.  It  is  much  easier  to  apply 
this  electrode  by  spreading  than  by  any  other  method, 
as  the  successive  movements  from  side  to  side  keep  the 
puddle  of  deposited  metal  in  the  centre  as  a  river  of 


SPREADING 


153 


metal  with  banks  of  slag,  and  as  advance  is  made  the 
banks  of  slag  close  over  the  metal  a  short  distance  be- 
hind the  arc.    This  electrode  in  starting  or  restarting 
the  cold  slag  must  be  chipped  away,  and  it  should  be 
noted  that  the  slag  must  be  cold,  i.e.,  black  before  it  can 
be  chipped  away.    In  merging  the  spreaded  beads  in 
these  electrodes  the  edge  to  be  merged  must  be  chipped 
clean,  else  there  is  almost  a  certainty  of  slag  inclusion  in 
the  weld.   In  spreading  with  a  flux-coated  electrode  the 
bare  side  should  be  kept  pointed  towards  the  parent 
metal,  and  it  will  be  noted  that  the  flux  coating  forms 
an  insulating  slag,  so  that  with  a  close  arc  it  is  a  natural 
tendency  to  advance  at  the  edge  of  the  previous  layer  or 
bead,  and  not  to  back  up  on  the  already  deposited  metal. 
With  bare  wire  there  is  no  svich  aid  and  special  care 
must  be  taken  to  not  bridge  over  or  leave  voids  in  this 
method  of  spreading,  i.e.,  bare  wire  is  least  applicable  to 
this  method  and  completely-coated  wire  is  most  appli- 
cable, while  the  half-coated  flux-covered  lends  itself  to 
either  spreading  or  padding  by  beads.    Correct  spread- 
ing is  shown  at  Fig.  36&  with  the  welded  metal  sunk 
in,  or,  as  the  experienced  welder  terms  it,  bit  into,  the 
parent  metal.    Spreading  with  too  long  an  arc  results 
in  the  deposited  metal  simply  lying  on  the  parent  metal 
as  at  Fig.  36c,  with  no  biting-in  effect.   Fig.  36e  shows 
how  padding  can  be  accomplished  by  spreading,  care 
being  taken,  of  course,  to  merge  the  spread  layers  into 
each  other,  and  it  will  be  noted  that  this  method  is  more 
applicable  to  a  small  amount  of  beading  whereas  beads 
are  more  applicable  wherever  the  surface  has  to  be  raised 
higher.    In  general  more  heat  and  hence  with  the  same 
length  of  arc  more  current  can  be  used  in  spreading 


154 


SPOT  AND  ARC  WELDING 


than  by  any  other  method,  and  with  speed  or  rate  of 
deposition  of  the  metal  with  the  arc  at  constant  length 


/mm  mM 


llllllllllllllllllllllillllllllllllllllllllKlllllllKlillliniH  


(b) 


CORRECT  SPREADING 


SPREADING  AT  TOO  GREAT 
A  SPEED 


(d) 


THIN  LAYER  PADDING  BY  SPREADING 


WELD  FROM 
BOTH  SIDES 


(e) 


ORIGINAL  BUTT  JOINT 

^^"^    BEFORE  WELDING 


WELDING  BUTT  JOINTS  BY  SPREADING  ON  THIN  WORK- 
'//e"-  %2"  STEEL,    '/a  "-/^e"  CAST  IRON  AND 
AUTO-SPRING  HIGH  CARBON  STEEL, 


(f) 


(9)  'mm^^^^m 


(h) 


SPREADING  WELDING  OF  THIN  STEEL  BUTT  JOINTS  WITH 

COOLING  BACKING 


WELDING  FROM  ONE  SIDE  ONLY 
Fig.  36. — Spreading. 


depends  on  the  current;  greater  speed  can  be  made  by 
spreading  than  by  any  other  method.    This  is  because 


SPREADING  155 

the  parent  metal  is  advanced  over  at  a  more  rapid  rate 
and  hence  a  greater  rate  of  heat  in  the  arc  can  be  taken 
care  of  by  the  weld  conducting  the  heat  of  the  arc  into 
the  parent  metal.  It  is  this  action  of  heat  conduction  by 
welding  that  allows  of  the  high  temperature  of  the  arc 
to  be  the  correct  results  from  mass  temperature  for 
molten  iron  and  other  metals.  The  fact  that  a  weld  is 
made  conducting  the  heat  away,  and  if  a  weld  was  not 
made  as  would  be  the  case  in  depositing  steel  on  a  cop- 
per plate,  the  deposited  metal  would  be  burned  beyond 
recognition  at  a  rate  of  heat,  and  hence  current  adjust- 
ment with  the  right  length  of  arc  would  be  perfectly  cor- 
rect when  welding  into  steel.  Figs.  36g  and  /  show  an 
application  of  spreading  to  a  butt-joint  on  thin  work. 
By  thin  work  is  meant  from  1/16-inch  to  5/32-inch  steel 
and  ^-inch  to  5/16-inch  cast  iron,  or  high-carbon  steel, 
such  as  an  automobile  spring.  Work  thinner  than  1/16 
inch  should  be  backed  up  as  in  Fig.  36/^,  with  a  cold 
mass  such  as  another  piece  of  steel  or  a  water  pad,  so 
that  the  metal  when  molten  for  welding  will  not  fall 
through.  If  the  piece  is  of  such  thickness  as  in  e  and  / 
that  the  spreading  will  not  melt  the  edges  so  as  to  fall 
through,  a  spread  can  be  put  on  both  sides  which  will 
merge  in  the  centre  as  shown,  and  weld  without  any  prep- 
aration of  the  joints.  Automobile  springs  being  about 
3/16  inch  to  ^4  thick  can  be  welded  successfully  in 
this  manner,  and  the  excess  metal  of  the  spread  ground 
off.  The  reason  spreading  is  used  for  this  comparatively 
thin  work  is  the  phenomenon  that  in  proceeding  with  a 
bead  the  edges  become  too  hot  and  fall  through,  whereas 
in  lacing  back  and  forth,  as  in  spreading,  more  of  the  heat 
is  carried  into  the  parent  metal. 


156 


SPOT  AND  ARC  WELDING 


"  Lesson  III 

PADDING 

"  Padding  in  general  is  a  succession  of  beads  run 
parallel  to  each  other  and  offers  a  great  field  for  useful- 
ness in  building  up  worn  parts  or  parts  machined  down 
too  far  for  subsequent  machining  to  correct  size.  In 
laying  these  pads  parallel  the  electrode  must  be  held  so 
that  the  arc  bites  into  the  preceding  pad  and  the  parent 
metal  at  the  same  time,  as  shown  in  Fig.  37a.  .  If  the  arc 
is  held  as  in  Fig.  37b  a  good  joint  will  be  had  to  the 
parent  metal,  but  little  or  no  joint  to  the  first  bead,  and 
in  machining  these  welds  voids  will  be  found  as  black 
slag  spots,  as  can  be  imagined  from  Fig.  37/.  Fig.  37c 
shows  these  beads  correctly  merged,  and  Fig.  37^  shows 
the  beads  perfectly  welded  to  the  plate  but  no  merging, 
and  hence  no  good  for  subsequent  machining.  In  com- 
mercial padding  the  choice  of  running  the  beads  length- 
wise or  crosswise  of  the  work  is  to  be  had,  and  in  general 
lengthwise  is  the  more  desirable,  as  the  piece  has  more 
time  to  absorb  the  excess  heat  of  the  arc  before  return- 
ing to  supply  more  heat.  In  either  case  the  outer  edge 
should  be  gone  around  with  the  bead  for  each  layer,  so 
that  a  sort  of  trough  can  be  formed  while  the  metal  is 
cool  and  shows  the  least  disposition  to  run  away.  For 
quick  rough  work  this  trough  could  then  be  filled  in  by 
spreading,  but  in  general  successive  lines  of  beads  is  the 
more  reliable  method.  After  the  method  of  a  reasonably 
smooth  pad  on  a  horizontal  flat  surface,  if  attained,  mak- 
ing a  pad  on  a  vertical  surface  is  next  in  order,  running 
a  bead  horizontally  with  successive  beads  directly  over 
it  and  later  making  the  pad  both  from  the  bottom  up  in 
vertical  layers  horizontally  and  from  the  top  down.  In 


PADDING 


157 


making  these  pads  overhead  it  will  be  noted  that  the 
only  hard  bead  to  put  up  there  is  the  first  one,  and  when 


FIRST  BEAD 


CRATER 


CORRECT 


CORRECTLY  MERGING  BEADS 


ELECTRODE 
(b) 

,ARC 

CRATER 


INCORRECT 


INCORRECT- NO  MERGING 


(d) 


SUCCESSIVE  LAYERS 
CORRECTLY  MERCED 


INCORRECT 
VOIDS,  SLAG,  AND  BLACK 
SPOTS  IN  WELD 


(f) 


LAYERS  or  OXIDE 


(S) 


LAYER  OF 

Fig.  37— Padding. 


LONG  ARC  EFFECT  ON  PADDING 


welding  against  this  first  bead  and  the  parent  metal  the 
student  will  be  able  to  notice  correct  conditions  for 
drawing  the  arc  equally  from  both,  as  in  that  case  the 


158 


SPOT  AND  ARC  WELDING 


metal  shows  the  least  disposition  to  fall.  The  overhead 
welding  has  no  function  of  negative  or  positive  polarity, 
but  simply  the  fact  that  one  liquid  drop  will  remain  on 
the  ceiling,  excess  over  one  drop  falls,  leaving  one  there, 
is  the  secret  of  overhead  welding.  It  has  probably  been 
noted  before  this  that  in  welding  no  drops  should  appear 
at  the  end  of  the  electrode,  i.e.,  when  the  arc  is  held  the 
right  length  and  the  metal  flows  evenly,  the  metal  of  the 
electrode  passes  through  the  fluid  bowl  as  a  gas  or  vapor 
and  condenses  on  the  parent  metal  as  a  liquid,  rapidly 
changing  into  a  viscous  and  then  a  solid  mass.  The  rip- 
pling appearance  of  the  finished  weld  being  successively 
frozen  ripples  of  the  liqviid  pool  due  to  the  magnetizing 
effect  of  the  current  in  the  arc  when  just  at  the  point  of 
freezing.  In  general,  overhead  welding  requires  more 
current  for  the  same  conditions,  as  the  arc  must  be  held 
closer,  which  means  slightly  less  voltage,  and  hence  to 
make  up  the  same  heat  the  current  must  be  raised.  As 
stated  before  the  one  trick  in  overhead  welding  is  in 
getting  started  and  holding  an  absolutely  unbroken 
close  arc.  A  great  aid  in  holding  this  close  arc  is  for  the 
student  to  rest  his  body  and  left  elbow,  if  he  is  right- 
handed,  against  the  piece  to  be  welded,  steadying  his 
right  hand  holding  the  electrode  holder. 

"  Another  way  is  to  put  the  right  elbow  up  against 
the  overhead  surface  and  to  use  the  elbow  as  a  centre 
and  guide  for  bringing  the  hand  and  electrode  up  at  an 
even  rate.  In  overhead  welding  the  student  will  best  see 
how  the  electrode  must  be  fed  into  the  weld  at  the  exact 
rate  the  electrode  is  being  melted.  Another  method  still, 
in  order  to  feed  the  electrode  at  an  even  rate,  is  to  use  the 
elbow  of  the  welding  hand  resting  on  the  knee  and  rais- 


PADDING 


159 


ing  the  toe  at  the  rate  desired.  Another  permissible 
method  for  welding  and  especially  useful  in  overhead  or 
vertical  welding  is  to  use  a  stick  similar  to  an  artist's 
maul-stick.  Overhead  welding  even  when  unsuccessfully 
tried  shows  what  is  required  for  first  and  successful  pads 
more  quickly  than  any  amount  of  verbal  or  written  in- 
structions. Padding  by  beads  should  only  be  done  with 
bare-wire  or  flux-coated  electrodes,  as  coated  electrodes 
are  only  successfully  applied  by  spreading,  as  shown  in 
the  second  lesson.  The  one  thought  necessary  in  suc- 
cessful padding  is  the  merging  of  the  pads  with  the 
parent  metal  and  with  each  other."  ^ 

^  TTiese  lessons  are  published  in  full  by  the  Electric  Arc  Cutting  & 
Welding  Co.,  Newark,  N.  J.  They  were  communicated  to  the  Author  by  Mr. 
C.  J.  Holslag,  chief  engineer  of  the  company. 


CHAPTER  VIII 


The  All- welded  Ship 

The  first  and  last  resolution  of  the  group  of  experts 
gathered  to  advise  the  Emergency  Fleet  Corporation  on 
the  use  of  electric  welding  in  the  ship  progi-am  urged  the 
building  of  an  all-welded  ship.  The  last  resolution 
carried  with  it  the  request  for  the  organization  to  be 
formed  and  the  money  to  be  appropriated  for  this  pur- 
pose. Such  requests  were  never  followed  by  authoriza- 
tion, and  the  all-welded  ship,  like  other  innovations,  was 
for  one  reason  or  another  never  started.  The  advocates 
of  the  process  never  halted  in  their  endeavors  to  suggest 
means  of  obtaining  permission  to  build  such  a  vessel  and 
many  progressive  shipbuilders  offered  to  undertake  the 
construction  if  formally  approved. 

In  the  early  deliberations  it  was  not  felt  that  the  pro- 
posal to  build  a  welded  ship  would  be  immediately 
acceded  to,  but  when  certain  practical  tests  and  demon- 
strations were  completed  there  would  result  no  hesitancy 
on  the  part  of  those  in  authority.  This  view  was  con- 
sistent with  the  times  as  greater  innovations  were  readily 
sanctioned.  So  that  no  time  might  be  wasted,  the  inves- 
tigational work,  both  practical  and  theoretical,  was 
pushed  with  all  haste,  data  in  gi'cat  quantities  gathered, 
and  the  educational  work  was  laid  down  in  some  syste- 
matic form.  Without  a  gi'cat  deal  of  effort,  it  was  found 
that  the  shipbuilders  were  using  the  process  very  spar- 
ingly and  efforts  were  made  to  find  the  reason  why  the 

160 


THE  ALL-WELDED  SHIP 


161 


non-essential  parts  of  the  riveted  ship  were  not  arc 
welded.  Some  shipbuilders  were  doing  a  little  of  this 
work  but  wished  to  do  more,  and  the  question  of  permis- 
sion rested  with  the  classification  societies.  TJiis  excuse, 
if  it  were  such,  was  soon  expunged  by  a  joint  approval 
by  Lloyd's  Register  and  the  American  Bureau  of  Ship- 
ping of  a  list  of  ship's  fittings  which  could  be  arc  welded 
(see  Appendix).  It  was  objected  that  this  list  referred 
only  to  jobs  with  which  ordinarily  classification  societies 
did  not  concern  themselves.  These  societies  had  gone  fur- 
ther by  a  clear  statement  that  upon  submittal  with  full 
information  they  would  consider  for  approval  proposals 
for  arc  welding  other  parts  of  the  vessel."  It  was  this 
last  expression  that  gave  rise  to  the  probable  extension 
of  arc  welding  to  a  standard  riveted  ship  with  the  result 
that  a  special  committee  was  appointed  to  give  views  on 
this  subject. 

Welding  a  Standard  Riveted  Ship. — Realizing  fully 
the  greater  benefits  that  would  accrue  in  a  welded  ship 
designed  from  the  point  of  view  of  this  process,  still  it 
was  believed  that  the  standard  riveted  construction  could 
be  more  expeditiously  put  together  with  the  electrode 
than  by  riveting,  riveting  work  being  at  that  time  the 
reason  claimed  by  shipbuilders  for  the  delay  in  ship  de- 
liveries. The  steel  shapes  and  plates  were  being  deliv- 
ered by  the  mills  in  ample  time;  and  quantities  of 
material  unfabricated  could  be  assembled  in  the  way 
selected.  This  naturally  would  not  show  the  saving  in 
cost  nor  the  reduction  in  materials  and  weight  that  was 
inherent  in  the  electric-welding  process  when  used  to  the 
full ;  but  still  there  would  be  a  small  percentage  of  sav- 
ing. The  main  assumption  was  not  commercial  economy 
11 


162 


SPOT  AND  ARC  WELDING 


but  saving  of  time,  the  serious  problem  then  facing  the 
country.  The  report  of  this  sub-committee  showed  that 
speedy  construction  would  follow  the  omission  of  water- 
tight stapling  required  in  riveted  ships,  the  omission  of 
all  cementing  of  decks  to  the  shell,  as  the  electrode  could 
guarantee  water-tightness,  the  omission  of  all  laps,  liners, 
jogglings,  straps,  etc.,  in  the  shell  plating  above  the 
bilge  by  employing  butt-welded  seams — the  same  thing 
was  recommended  for  decks.  Riveting  of  shell  plates  to 
frames  was  suggested  as  a  conservative  measure.  Spot 
welding  of  the  brackets  to  frames  or  beams  and  the  spot 
welding  of  floor  plates  to  frames,  reverse  frames  and 
clips,  was  considered  feasible  if  done  in  the  shop  and 
these  assembled  parts  arc  welded  to  the  other  members 
in  the  ship.  Spot  welding  was  also  recommended  for  the 
attachment  of  cargo  battens  and  other  fittings.  Addi- 
tional suggestions  included  all  non-strength  members, 
all  deck  erections,  smoke  pipes,  up-take,  ventilators, 
ducts,  combings  for  hatches,  and  man-holes,  door  framejs, 
separately-built  tanks,  lockers,  and  racks.  The  masts, 
booms,  shaft  and  pipe  tunnels,  and  similar  cylindrical 
work  usually  riveted  in  two  pieces  were  to  be  welded 
throughout,  omitting  the  straps.  Cast-steel  fittings 
were  to  be  welded  to  plates.  Oil  tanks  were  to  be  welded 
"  even  in  conjunction  with  riveting."  Swash  plates 
could  be  tack  welded  to  decks  and  bulkheads  omitting 
the  flanges  in  order  that  these  plates  might  be  washed 
away  without  endangering  the  hull  proper.  The  recom- 
mendations also  include  the  welding  of  all  stanchions 
both  head  and  heel,  pipe  railing,  and  all  flanges  on  steel 
pipe  and  tubing. 

It  is  easy  to  see  that  this  detail  list  covers  the  welding 


THE  ALL- WELDED  SHIP 


163 


of  approximately  90  to  95  per  cent,  of  the  ship.  In  fact, 
it  only  reserves  for  riveting  the  main  strength  members 
of  the  hull.  This  suggestion  was  never  put  into  effect. 
It  occasioned  a  full  discussion  on  the  merits  of  combin- 
ing arc  welding  with  riveting  and  established  the 
opinion  that  an  arc- welded  and  riveted  joint  was 
not  satisfactory. 

For  emergency  repairs  certain  riveted  joints  had 
been  arc  welded  along  the  edge  instead  of  caulking. 
The  damaged  part  had  destroyed  the  caulking  edge. 
These  jobs  were  carefvilly  watched.  The  riveted  joint, 
if  not  reinforced  by  a  strength  weld,  i.e.,  if  the  edges 
were  simply  made  water-tight  with  a  fillet  weld,  due  to 
the  creeping  action,  would  throw  the  strain  upon  the 
welding.  The  water-tightness  of  the  joint  would  then 
be  impaired.  If  a  strength  weld  were  made  on  the  edge, 
all  strains  would  be  taken  off  the  rivets  and  they  would 
serve  no  good  purpose.  In  repair  work  it  was  found  de- 
sirable to  weld  on  a  thin-flanged  piece  over  the  entire 
riveted  joint.  This  flanged  piece  allowed  sufficient  play 
to  the  riveted  joint  and  yet  would  not  tend  to  open  the 
welded  joint.  In  this  manner  a  good  water-tight  job 
could  be  obtained. 

Welded  Craft. — As  far  as  is  known  the  first  water 
craft  to  be  partially  electrically  welded  is  the  Dorothea 
M.  Geary,^  a  motor  boat  built  of  steel  and  42  feet  in 
length.  She  was  launched  about  the  end  of  November, 
1915,  and  is  used  for  ship  repairs  in  Ashtabula  Harbor, 
Ohio.  Although  the  small  size  of  this  boat  and  the  thin 
plating  (about  3/16  inches  thick)  used  for  shell  and 

'"The  First  Electrically-Welded  Boat,"  John  Liston,  General  Electric 
Review,  December,  1918. 


164 


SPOT  AND  ARC  WELDING 


decks  may  not  assure  the  conservatives  that  10,000-ton 
ocean-going  cargo  vessels  may  be  built  likewise,  yet  the 
record  of  the  boat  in  service  is  remarkable  from  the 
standpoint  of  the  strength  and  fatigue-resisting  quali- 
ties of  electric  welds.  On  December  17,  1915,  shortly 
after  the  launching,  a  call  for  repair  work  was  received 
from  Fairport  Harbor,  distant  about  30  miles,  and  al- 
though Lake  Erie  shipping  was  practically  suspended 
at  that  time  owing  to  weather  conditions,  the  welded  boat 
was  at  once  headed  into  the  lake  which  was  covered  with 
floe  ice  and  made  the  run  to  Fairport  in  about  three  and 
one-half  hours.  When  the  harbor  was  reached  it  was 
foimd  to  be  covered  with  fom-  inches  of  solid  ice,  and 
into  this  the  welded  boat  was  rammed,  breaking  her  way 
through,  at  reduced  speed  but  without  a  stop,  to  the 
pier  where  the  ship  she  was  to  work  on  was  laid  up.  After 
the  return  to  Ashtabula  careful  inspection  of  the  boat 
failed  to  show  that  any  injury  had  been  sustained."  ^ 

And  again:  ''In  the  following  year  an  accident 
occurred  which  threatened  to  destroy  the  welded  boat. 
Work  was  being  performed  aboard  the  freighter  Aleoois 
Tliompson  in  the  Superior  Slip  at  Ashtabula,  the  welded 
boat  lying  alongside,  when  the  freighter  C.  Russell 
Hubbard,  which,  moored  at  the  opposite  side  of  the  slip, 
broke  adrift,  swung  across  the  slip,  literally  squeezing  the 
small  craft  between  the  two  large  freighters.  .  .  .  The 
sides  of  the  welded  boat  being  crushed  into  a  maximum 
distance  of  18  inches  amidships.  .  .  .  This  damage 
was  repaired  by  means  of  jacks  which  were  used  to  force 
the  sides  back  into  normal  position.   .    .    .    Leaks  were 

^ "  The  Electrically-Welded  Boat,"  John  Liston,  General  Electric  Re- 
vieic,  December,  1918. 


THE  ALL- WELDED  SHIP 


165 


started,  but  investigations  showed  that  they  were  again 
due  to  loosened  rivets  and  not  to  any  failure  of  the  weld." 

The  edges  of  the  plates  were  V'd  for  butt  welding 
and  a  metallic  electrode  was  used  of  approximately  the 
following  constituents:  Carbon,  0.10  per  cent.;  man- 
ganese, 1.87  per  cent.;  and  a  trace  of  silicon.  The  keel 
was  electrically  welded,  but  the  hull  plating  was  riveted 
to  the  frames  and  keel,  and  the  structure  above  the 
deck  line  was  riveted  and  strengthened  with  angle  iron." 
The  welded  seams  were  left  reinforced,  and  after  welding 
were  "  pneumatically  hammered." 

In  1917,  a  60-foot  section  of  a  1200-ton  bulk-oil  barge' 
was  electrically  welded  in  this  country.  The  remainder 
of  the  barge  was  the  usual  riveted  constrviction.  This 
craft  was  for  service  in  Mexico.  She  was  165  feet  long, 
38-foot  beam,  and  about  8  feet  6  inches  in  depth.  She 
was  constructed  of  ^-inch  plates  for  decks  and  shell, 
and  the  transverse  members  were  of  5/16-inch  plating. 
It  is  stated  that  this  barge  carried  nearly  a  full  cargo 
from  New  York  to  Tampico,  a  distance  of  2500  miles 
on  the  ocean,  without  harm  to  hull  or  cargo.  "  No  re- 
pairs have  thus  far  been  required,  notwithstanding  the 
barge  has  been  in  service  about  twelve  months  as  a  bulk- 
oil  carrier  on  the  Panuco  River,  where  the  rapid  currents, 
wind,  and  tide,  combine  to  make  navigation  difficult." 

Reference  has  already  been  made  to  welding  activi- 
ties in  England.  In  the  early  part  of  1918  there  was 
built  an  all-welded  cross-channel  barge.^  This  craft  had 
a  deadweight  carrying  capacitj^  of  275  tons.  The  frames 
were  2^  X  2^  X  ^4 -inch  steel  angles,  the  floors  were 

^  Report  of  Capt.  James  Caldwell  to  the  U.  S.  Shipping  Board,  1918. 
*  Report  of  Capt.  James  Caldwell  to  the  U.  S.  Shipping  Board,  1918. 


166 


SPOT  AND  ARC  WELDING 


7  X  X  7/20-inch  angles,  and  the  shell  and  deck 
plating        inches.    The  edges  of  the  shell  plating  were 

joggled  in  order  to  provide  flat  welding  and  to  reduce 
overhead  welding  to  a  minimum.  Holes  were  punched 
for  assembling  the  vessel  in  the  regular  manner.  These 
holes  were  spaced  about  10;^  inches  to  receive  the  service 
bolts  for  erection  purposes.  After  the  welding  was  com- 
pleted, the  holes  were  closed  by  the  electrode.  The  shell 
seams  were  full  welded  on  the  exterior,  but  tack  welded 
on  the  interior.  She  was  divided  by  three  water-tight 
bvilkheads.  The  hull  was  flat  and  there  were  four  strakes 
of  plating  to  each  side. 

Though  minor  leaks  were  discovered  on  the  first 
loading,  the  barge  has  been  in  successful  use  across  the 
channel  and  has  shown  no  signs,  according  to  last  re- 
ports, of  anything  detrimental  to  the  process. 

Careful  records  of  time  and  cost  were  kept  for  com- 
parison with  riveted  barges  of  the  same  size  and  type. 
It  is  interesting  to  note  that  the  total  cost  of  electric 
welding  was  $1500.  Of  this  item  $310  represented  cost 
of  labor,  $300  the  cost  of  current,  and  $890  the  cost  of 
electrodes.  This  latter  item  is  high,  due  to  the  use  of  the 
slag-covered  electrodes,  which  is  the  approved  practice 
in  England. 

Next  of  interest  is  the  time  of  welding.  At  the  com- 
mencement of  the  work,  the  average  was  about  4  feet 
an  hour,  but  towards  the  completion  this  increased  to 
about  7  feet  an  hour.  During  the  work  a  maximum  of 
14  feet  an  hour  was  attained. 

In  1918,  arrangements  were  completed  for  the  elec- 
tric welding  of  a  battle-towing-target  keel,  to  be  built  at 


THE  ALL- WELDED  SHIP 


167 


the  Norfolk  Navy  Yard.  This  structure  is  built  of  steel 
shapes  and  plates,  and  functions  under  water  to  support 
the  wooden  target  which  is  destroyed  by  gun  fire.  Al- 
though not  rightly  classed  as  a  water  craft,  still  the 
shock,  strains,  and  stresses  that  are  so  much  the  concern 
of  those  who  design  and  build  steel  vessels  will  be  suf- 
fered by  this  keel.    It  is  unnecessary  to  detail  the  con- 


FiG.  38. — Battle-to  wing- target  keel. 


struction  elements.  A  very  good  idea  of  the  keel  is 
given  in  Fig.  38.  This  structure  is  now  completed  and 
awaiting  the  wooden  super-structure.  When  this  latter 
is  built  and  their  combination  effected,  the  entire  target 
will  be  tested  at  sea.  Full  reports  of  the  trial  of  this 
keel  in  service  will  probably  be  available  after  the  navy 
has  completed  its  investigations. 

Patented  Designs. — During  the  war,  two  American- 
patented  designs  for  welded  ship  constructions  were 
patriotically  offered  for  the  use  of  the  Emergency  Fleet 


168 


SPOT  AND  ARC  WELDING 


Corporation.  As  will  be  seen,  these  designs  were  not 
accepted,  and  drawings  were  prepared  for  a  proposed 
welded  ship  by  a  special  sub-committee.  Without  enter- 
ing into  a  mass  of  patent  claims,  one  of  these  American 
designs  ^  was  characterized  by  omitting  many  of  the 
small  connection  pieces  used  in  regular  riveting  con- 
struction and  thus  reducing  weight  and  cost.  By  tack 
welding  of  clips  and  lever  fulcrums  temporarily,  the 
usual  run  of  badly  twisted  shapes  and  plates  could  be 
straightened  preparatory  to  welding.  By  this  same 
method  it  was  claimed  that  an  entire  ship  could  be  easily 
assembled  without  the  use  of  assembly  bolts,  thus  avoid- 
ing the  expense  and  damage  to  the  work  material  by 
punching  holes.  As  the  fulcrum  clips  and  handling 
attachments  were  only  lightly  welded,  they  could  be 
readily  knocked  off  the  original  metal  with  little  loss  of 
time  and  no  damage. 

The  other  American  design  ^  was  based  funda- 
mentally upon  the  conception  that  angle  bars,  which  are 
necessary  to  a  riveted  connection,  were  unnecessary  for 
the  welded  connection.  With  this  in  view,  the  construc- 
tion of  a  vessel  was  reduced  to  the  use  of  plating  through- 
out. The  design  carried  the  requirement  that  one  edge 
of  the  plate  be  flanged.  Thus  in  the  case  of  the  shell 
plating  the  flange  served  as  a  continuous  longitudinal 
member.  The  design  embodies  the  best  strength  quali- 
ties with  reduction  of  weight  of  both  the  transversely- 
and  longitudinally-framed  vessels.  By  cutting  notches 
in  the  straight  edge  of  the  plates  at  desired  intervals, 
bolts  could  be  used  to  draw  vip  and  secure  the  work  for 

^  Capt.  J ames  Caldwell's  Report  to  the  U.  S.  Shipping  Board,  pp.  109 
and  93,  1918. 


THE  ALL- WELDED  SHIP 


169 


welding.  This  method  of  assembly  was  not  essentially 
different  from  present  practice.  The  main  objection  to 
this  design  was  the  fact  that  the  plates  must  be  flanged  at 
the  mill,  as  the  run  of  ship  structural  steel  would  not 
permit  of  cold  flanging.  As  the  larger  percentage  of 
material  was  required  to  be  flanged,  it  would  seem  from 
the  standpoint  of  standardization  that  the  design 
merits  consideration. 

An  English  patent  shown  in  this  country  differs 
from  the  last  American  design  in  that  it  clung  to  the 
angle-bar  connection.  Instead  of  employing  continuous 
welds  along  the  edges  of  the  angle,  it  preferred  to  notch 
out  the  angle  flanges  with  desired  spacing  and  then  arc 
weld  at  the  notching,  if  the  bounding  bars  were  simply 
for  holding  together  non- water-tight  members.  If  the 
compartment  was  to  be  water-tight,  then  one  edge  and 
the  notching  of  the  angle  bars  were  welded.  Straps 
were  prepared  with  elliptical  holes,  so  that  they  would  be 
welded  as  well  as  the  edges.  The  whole  design  was  con- 
sidered from  the  point  of  view  of  the  fusion  of  all  the 
parts  requiring  to  be  joined.  In  such  places  as  the  inner 
bottom  of  the  ship,  where  lengths  of  moderately-thin 
plating  would  affect  the  jointure  by  panting  or  fatigue 
stresses,  brackets  formed  by  angle  bars  were  welded  as  re- 
quired. Evidently  this  design  had  in  mind  the  reduction 
of  welding,  but  seemingly  the  preparatory  work  on  the 
original  materials  would  exceed  the  saving  in  arc- 
welding  labor  and  materials.  In  view  of  the  American 
design  discarding  the  angle  bar,  and  the  results  of  tests 
of  both  butt- welded  joints  in  flat  plates  and  cross  con- 
nections, apparently  there  is  little  merit  in  this 
patented  construction. 


170 


SPOT  AND  ARC  WELDING 


Emergency  Fleet  Corporation  Design.^ — This  de- 
sign was  made  under  pressure  due  to  the  exigency  of 
the  time.  No  more  than  three  weeks  were  given  for  the 
preparation  of  complete  drawings  of  both  the  ship  and  a 
proposed  yard  in  which  to  build  her.  At  that  particular 
time,  no  shipbuilder  would  consider  the  proposition  of 
building  any  more  ships.  There  was  a  growing  shortage 
of  labor,  and  riveters  were  scarce  and  costly.  The  objects 
sought  in  this  design  were  a  ship  that  could  be  quickly 
manufactured,  not  built,  a  method  of  shop  procedure 
that  would  not  make  further  demands  on  a  depleted  labor 
market,  and  yet  a  restriction  of  design  that  would  not 
exceed  the  possible  workings  of  the  economic  law. 

For  general  outlines,  accommodations,  propulsive 
machinery,  etc.,  a  standard  ship  was  taken  as  a  guide. 
The  majority  advice  of  welding  experts  was  taken  in 
the  adoption  of,  and  the  approximation  of,  percentage 
strength  of  the  electrically- welded  joints.  At  that  time, 
the  consensus  of  opinion  was  that  the  strap- joint  with 
three  full-strength  welds  was  the  strongest  joint.  This 
design  of  joint  was  used  in  all  connections  of  principal 
members.  Where  plates  met  at  right  angles  in  cruci- 
form, full-strength  welds  were  provided.  At  the  time 
of  design,  it  was  considered  conservative  to  provide  a 
bearing  strip  to  distribute  the  thrust  where  a  plate  was 
connected  at  right  angles  to  another  unsupported  plate. 
After  discussion  on  this  point,  other  methods  were  sug- 
gested for  overcoming  this  difficulty  without  resort  to 
the  bearing  strip  which  in  the  minds  of  some  experts  was 
a  detriment  to  the  connection. 

Perhaps  the  most  radical  departure  from  a  ship- 

^  Supplement  of  Nauticiis,  June  1,  1918,  N.  Y, 


THE  ALL- WELDED  SHIP 


171 


design  viewpoint  was  the  use  of  transverse  plating  in- 
stead of  the  customary  longitudinal  plating.  When  the 
design  was  first  discussed  the  question  was  asked :  What 
is  the  function  of  the  shell  plating  of  a  ship  ?  The  reason- 
able answer  is  contained  in  the  familiar  name  "  the  skin 
of  the  ship/'  i.e.,  it  keeps  the  water  from  coming  in  and 
prevents  the  cargo  from  going  out.  In  short,  the  shell 
of  the  ship  has  but  a  small  share  in  the  strength  of  the 
ship.  In  this  design,  the  strength  of  the  hull  was  more 
than  conservatively  designed.  The  keel,  the  centre  keel- 
son, rider,  bilge  plate,  shear  strake,  and  upper-deck 
stringer,  were  planned  in  long  lengths  and  with  few 
joints.  These  joints  were  carefully  distributed.  The 
calculations  of  the  naval  architect  showed  that  a  section 
through  the  cargo  hatch  as  designed  was  stronger  by  10 
per  cent,  than  the  riveted  vessel.  The  practical  purpose 
served  by  the  transverse  plating  was  that  it  gave  a  method 
for  manufacturing  ships. 

Adopting  a  6-foot-wide  plate,  the  design  provided 
for  putting  the  ship  together  in  sections  the  width  of  the 
transverse  plate.  Each  plate  was  fitted  in  the  shop  with 
two  frames  and  their  connections.  There  were  two  of 
these  pieces,  one  for  each  side  of  the  vessel.  Two  sections 
of  the  floor  were  likewise  built  in  the  shop  and  two  6- 
foot  deck  sections  with  two  beams  attached,  one  for  each 
deck,  completed  the  pieces,  making  up  one  6-foot  sec- 
tion. The  plan  of  operation  was  to  build  these  pieces 
under  shop-production  methods  and  so  arrange  the  work 
that  each  day  one  6-foot  section  of  the  vessel  would  be 
completed.  Thus  plans  could  be  made  ahead  of  time 
to  follow  a  strict  schedule.  As  these  details  would  be- 
come standard  procedure,  more  time  on  the  part  of 


172 


SPOT  AND  ARC  WELDING 


executives,  superintendents,  etc.,  could  be  devoted  to  the 
delays  usually  connected  with  the  fitting  up  of  the  vessel. 

To  meet  this  manufacturing  scheme,  a  yard  plan  was 
devised.  This  consisted  in  the  estabhshment  of  one,  and 
only  one,  way  to  build  the  ship,  from  stern  to  stem.  A 
crane  was  designed  to  move  up  the  ways,  handling  the 
pieces  from  the  shop,  until  they  were  securely  welded, 
and  then  moving  on  for  the  next  section.  This  was  more 
than  a  crane,  it  was  a  moving  shelter  for  the  men  and 
shops  with  the  addition  of  flexible  scaffolding.  The  esti- 
mates showed  that  a  6-foot  section  could  be  erected  and 
completely  welded  in  one  working  day  of  eight  hours; 
which  meant  that  when  such  a  shipyard  was  working 
under  its  best  efficiency  that  a  standard  ship  of  410  feet 
could  be  completed  in  seventy-five  working  days.  This 
estimate  is  on  the  basis  of  a  single  shift  of  operators. 

The  designs  as  submitted  were  widely  criticised,  and, 
curiously,  on  one  point,  namely,  that  it  was  not  a  rivet- 
less  ship.  The  frame  brackets  were  riveted  to  the  beams. 
This  was  considered  a  conservative  measure  by  the  design 
committee.  Opinions  were  pronounced  for  an  all- welded 
ship,  based,  no  doubt,  on  the  sentiment  that  an  innova- 
tion must  stand  on  its  own  feet.  Then,  as  time  went  on, 
shipbuilders  claimed  that  their  works  were  progressing 
so  rapidly  that  shortly  they  woidd  have  vacant  ways. 
There  would  be  no  necessity  for  a  special  yard  in  which 
to  build  the  first  welded  ship.  At  once  with  this  argu- 
ment, all  the  fundamental  reasons  for  its  being  deprived 
this  welded-ship  design  of  further  consideration.  No 
longer  did  there  exist  a  shortage  in  the  labor  market,  no 
longer  were  people  at  large  aroused  at  the  shortage  of 
ships,  no  longer  did  the  foreign  cables  cause  sensations. 


THE  ALL-WELDED  SHIP 


173 


and  no  longer  did  the  shipbuilder  worry  over  the  de- 
livery of  completed  tonnage.  And  soon  to  follow  this 
were  the  straws  of  the  Armistice. 

Isherwood  Welded  Ship. — Just  before  the  news  of 
the  cessation  of  hostilities,  Mr.  J.  W.  Isherwood  brought 
to  this  country  from  England  a  design  of  a  3900-ton 
deadweight  ship  which  could  be  electrically  welded.  The 
application  of  welding  was  made  to  his  well-known 
patented  longitudinally-framed  ship.  The  main  objects 
sought  were:  (1)  Adaptation  to  existing  shipyards,  i.e.j 
all  the  pieces  fabricated  in  the  shops  could  be  easily 
handled  on  the  ways  by  the  crane  service  provided  for 
riveted  ships;  (2)  a  careful  reduction  of  overhead  weld- 
ing, especially  in  the  field  work;  (3)  the  use  of  service 
bolts  as  customary  for  the  assembling  of  the  hull  mate- 
rials; and  (4)  the  small  amount  of  welding  necessary  in 
the  field.  Full  details  of  this  interesting  design  will  be 
found  in  the  Appendix.  Mr.  Isherwood  stated  that: 
"  This  design  was  prepared  by  me  in  London  with  the 
cooperation  of  Mr.  W.  S.  Abell,  Chief  Ship  Surveyor  of 
Lloyd's  Register  of  Shipping."  This  gives  added 
weight  to  the  design,  if  indeed  it  were  needed,  as  the 
inference  is  that  the  rules  of  Lloyd's  for  electrically- 
welded  ships  have  been  fully  considered.  The  designer 
has  provided  broadly  for  any  play  of  conservatism  that 
might  question  the  electrically- welded  process,  and  he  be- 
lieves as  a  matter  of  economy  that,  where  many  service 
holes  would  be  required  for  proper  fairing,  the 
punching  of  a  few  additional  holes  and  riveting  that 
particular  connection  might  result  in  an  increased  speed 
of  construction  and  a  reduction  of  cost.   In  general,  he 


174 


SPOT  AND  ARC  WELDING 


has  taken  the  very  best  and  safest  points  of  the  welding 
process  and  combined  them  with  the  best  and  most  cus- 
tomary shipbuilding  practice.  As  a  careful  study  of  his 
design  will  show,  every  eventuality  in  electric  welding 
has  been  considered  and  as  well  an  inclusion  of  the  pos- 
sible developments  of  the  art. 

With  this  design  as  a  basis,  it  was  not  difRcidt  to  in- 
crease the  size  of  the  vessel  to  5000  tons  deadweight. 
And  as  by  that  time  the  majority  opinion  was  favorable 
to  the  larger-sized  vessel,  negotiations  for  the  com- 
mencement of  work  on  a  design  of  this  type  were  about 
to  be  effected  through  the  formation  of  a  proper  organ- 
ization when  the  activities  in  electric  welding  were  post- 
poned, due  to  the  close  of  the  war. 

Lloyd's  RulesJ — Before  the  issuance  of  require- 
ments for  the  use  of  electric  welding  in  ship  construction, 
Lloyd's  Register  made  specific  investigations  of  a  tech- 
nical and  practical  nature.  That  is,  the  tests  were  made 
on  fairly-large  samples  and  careful  measurements  with 
delicate  instruments  were  taken.  Realizing  that  many 
tests  of  the  ultimate  tensile  strength  of  electric  welds 
had  been  made  but  that  other  and  more  important  char- 
acteristics of  the  joint  had  not  been  considered — ^these 
being  essential  to  the  construction  of  ships — experiments 
were  performed  to  determine  if  there  were  any  differ- 
ences in  the  modulus  of  elasticity  of  the  weld  and  ad- 
jacent plate;  or  at  least  a  diflference  that  would  prohibit 
the  use  of  the  process.  Experts  in  the  testing  of  steel 
were  not  surprised  at  the  results  which  showed  that  the 
difference  in  elasticity  between  the  weld  and  the  plain 


^  See  Appendix. 


THE  ALL-WELDED  SHIP 


175 


plate  is  negligible."  ^  This  deduction  was  made  upon 
the  completion  of  the  welded  sample,  but  the  same 
authority  states : To  obtain  further  information  regard- 
ing the  properties  of  this  deposited  material,  small  test 
pieces  were  prepared  entirely  composed  of  it,  and  the 
modulus  of  elasticity  thus  determined  was  found  to  be 
11,700  tons  per  square  inch  as  compared  with  about 
13,500  tons  for  mild  steel  and  12,500  for  wrought  iron." 

Although  ultimate  strength  tests  were  made  for  a 
comparison  between  treble-riveted  lap-joints  and  lap- 
welded  and  butt- welded  joints,  the  most  important  tests 
from  a  strvictural  viewpoint  were  those  subjecting  the 
joint  to  alternating  stresses.  The  results  indicated  that, 
whereas  the  welded  joint  would  break  down  under  re- 
peated stresses  (5,000,000)  with  6  tons  per  square  inch, 
the  unwelded  test  pieces  would  not  break  down  vmtil 
they  had  reached  10  tons  per  square  inch.  Alternating- 
stress  measurements  were  taken  on  various  types  of 
joints,  all  of  which  led  to  the  following  conclusion: 
"  These  tests  showed  generally  that  welded  material  will 
not  withstand  a  very  large  number,  say  several  millions 
of  alternations,  if  the  applied  stress  is  greater  than  about 
plus  or  minus  6  tons  per  square  inch.  The  capability  to 
resist  alternating  stresses  is,  of  course,  of  the  very  great- 
est importance  in  shipbuilding  materials,  and  would 
appear  for  the  present,  at  least,  to  limit  the  application 
of  welding  to  vessels  in  which  the  stress  is  not  exceeded. 
The  calculated  stresses  in  ship  structures  are  in  the  case 
of  large  vessels  rather  in  excess  of  this  figure,  although, 
from  such  information  as  is  available  on  the  subject,  it 

^  "  Electric  Welding  for  Shipbuilding  Purposes,"  W.  S.  Abell,  Journal  of 
East  Coast  Institute  of  Engineers  and  Shipbuilders,  1918. 


176 


SPOT  AND  ARC  WELDING 


would  appear  that  the  stress  actually  experienced  by  the 
material  in  a  ship  is  considerably  less  than  that  calculated 
under  the  usually-assumed  conditions.  It  is  well,  how- 
ever, to  proceed  cautiously  in  the  application  of  a  novel 
method  of  construction  like  electric  welding,  and  it  would 
probably  be  wise  to  limit  its  application  meantime  to 
vessels  whose  length  is  not  greater  than  about  300  feet."^ 

Specialists  in  electric  welding,  though  interested  in 
all  these  investigations,  were  disappointed  for  one  reason, 
namely,  that  the  welded  samples  were  all  made  by  one 
process.  In  a  practical  sense  this  may  be  looked  upon  as 
unfortunate,  but  in  a  technical  sense  the  maintenance  of 
a  constant  electrode  material,  current  adjustment,  and 
skill  of  operator  was  more  important.  One  of  the  diffi- 
culties to  the  introduction  of  electric  welding  has  been 
the  claims  of  those  who  prefer  some  special  system  or 
appliance.  And  confusion  must  result  where  all  the 
different  modifications  to  the  simple  practice  are  inter- 
mingled in  elaborate  tests.  Let  it  be  squarely  said  that 
Lloyd's  Register  has  announced  rules  which  require  a 
certain  process  to  be  employed.  They  have  also  an- 
nounced that  they  will  undertake  to  approve  any  process 
of  electric  welding  which  meets  their  rules  and  which  in 
the  judgement  of  their  technical  staff  qualifies  it  for  the 
joining  of  ship's  steel. 

Summary. — From  the  preceding  outline  of  the  de- 
velopment of  the  all-welded  ship,  it  will  be  seen  that  in 
this  coimtry  the  proposals  did  not  advance  beyond  the 
point  of  design.  In  England  it  proceeded  to  the  actual 
laying  down  of  a  coasting  vessel  150  feet  in  length.  The 

^"Electric  Welding  for  Ships,"  W.  S.  Abell,  Journal  of  East  Coast 
Institute  of  Engineers  and  Shipbuilders,  1918. 


THE  ALL-WELDED  SHIP 


177 


latest  advice  concerning  the  building  of  this  vessel  indi- 
cates that  the  work  is  proceeding  at  a  slow  rate.  The 
underlying  causes  are  concerned  with  commercial  mat- 
ters which  cannot  be  discussed  here.  With  the  removal 
of  the  impedimenta  surrounding  the  technical  ability  of 
the  welding  processes  to  joint  heavy  structural  pieces, 
there  can  exist  but  optimistic  feelings  that  practical 
obstacles  will  vanish  in  the  future. 


12 


CHAPTER  IX 


Theories  of  Electric  Welding 

It  is  proper  to  state  that  unfortunately  the  nomen- 
clature of  electric  welding  is  not  clear.  This  makes 
doubly  difficult  an  exploration  into  the  field  of  theories. 
In  the  matters  already  treated  the  terms  used  have  been 
those  customary  to  practice.  It  may  be  better  for  what 
is  to  follow  to  explain  the  general  conception  of  welding 
and  what  is  meant  by  autogenous  soldering "  or 
autogenous  welding." 

The  word  "  weld  "  in  accordance  with  the  dictionary 
is  of  Anglo-Saxon  origin,  probably  related  to  the  verb 
"  well/'  to  gush.  "  Welding,"  as  a  term  for  the  modern 
processes  of  joining  metals,  is  in  dispute.  Some  experts 
hold  that  it  is  not  fully  descriptive  of  what  takes  place 
in  the  process ;  others  claim  that  used  as  a  general  term 
it  creates  confusion ;  and  still  others  in  order  to  conserve 
time  immediately  divide  "  welding  "  into  two  parts,  call- 
ing one  "  pressure  welding  "  and  the  other  "  autogenous 
welding,"  and  proceed  to  define  these  branches.  His- 
torically, welding  as  performed  by  the  blacksmith  was 
the  union  of  two  pieces  of  metal  with  or  without  an 
external  source  of  heat  or  without  fusion.  That  is  to  say, 
that  metals  in  a  cold  state  can  be  united  by  pressure 
derived  by  striking  with  a  hammer,  although  the  force 
of  the  blows  or  friction  might  impart  some  heat  to  the 
union.  This  is  an  approach  to  a  generic  definition 
of  "  welding." 

178 


THEORIES  OF  ELECTRIC  WELDING  179 


Much  confusion  has  grown  around  the  use  of  the 
words  "  soldering  "  and  autogenous."  It  is  generally 
accepted  that  when  a  metallic  joint  is  affected  by  means 
of  some  external  unionizing  medium  which  adheres  to 
the  pieces  to  be  joined  and  closes  up  the  gap  between 
them,  this  is  "  soldering."  The  unionizing  medium  is 
usually  a  softer  metal  or  alloy  melting  at  a  lower  tem- 
perature than  the  parts  to  be  joined.  "  Brazing  "  does 
not  complicate  matters  because  the  term  is  used  restric- 
tively  for  a  hard  "  solder/'  one  that  melts  at  a  relatively 
high  temperature.  But  the  word  "  autogenous,"  said  to 
have  been  introduced  by  the  French,  gives  much  trouble. 
The  word  is  from  the  Greek,  and  means  self -generated. 
Evidently  considered  applicable  to  the  carbon-arc 
process  and  bxy-acetylene  process  when  joining  thin 
sheet  metal,  as  the  soldering  rod  was  not  requisite.  If  the 
term  autogenous  "  gives  the  conception  of  furnishing 
or  generating  its  own  heat,  then  those  who  claim  that  arc 
welding  with  the  metallic  electrode  should  be  called 
"  autogenous  soldering  "  are  not  without  justification. 
On  the  other  hand,  if  the  conception  of  metallic  arc 
welding  resides  in  the  electrical  view  that  the  heat  is  pro- 
duced by  the  arc  and  that  this  metallic  vapor  is  furnished 
by  an  external  source  of  energy,  there  can  be  nothing 
"  autogenous  "  about  it.  In  the  same  sense  this  word  is 
held  by  the  advocates  of  the  oxy-acetylene  process. 

Forgetting  terms  for  the  moment,  there  is  marked 
distinction  between  the  joining  of  metals  by  the  two 
electric  methods.  In  the  former,  called  "  welding," 
pressure  is  used  and  the  heat  is  localized  by  the  resist- 
ance to  the  flow  of  electric  current ;  in  the  latter  no  pres- 
sure is  applied  and  the  heat  is  localized  through  the 


180 


SPOT  AND  ARC  WELDING 


action  of  the  electric  arc.  These  characteristics  are  fully 
differentiated  by  the  accepted  nomenclature,  the  former 
termed  generically  resistance  welding,  and  the  latter  arc 
welding.  Of  these  genera,  two  species  have  been 
selected  for  special  investigation,  respectively,  "  spot 
welding  "  and  "  metallic  arc  welding." 

Spot  W elding, — There  are  very  few  theories  to  be 
found  for  the  effects  produced  by  spot  welding.  This 
is  specially  the  case  with  the  spot  welding  of  heavy  ma- 
terials as  the  development  in  this  line  is  of  very  recent 
date.  It  is  a  fertile  field  of  investigation  and  should  be 
undertaken  while  the  process  is  on  the  threshold  of  in- 
dustrial acceptance.  Some  work  was  done  in  the  related 
process  of  butt  welding,^  though  the  investigations  were 
cut  short  at  an  important  point.  The  heat  treatment  of 
steel  has  received  careful  study  because  the  employment 
of  this  metal  is  of  necessity  to  the  industries.  It  is  well 
known  that  the  grain  structure  of  steel  can  be  materially 
changed  after  being  strained  by  annealing.  It  is  an 
every-day  affair  in  manufacturing  lines  to  thus  remove 
the  harmful  effects  of  cold-worked  steel  or  to  soften, 
strengthen,  or  harden,  rolled  or  forged  steel  in  order  to 
adapt  its  physical  properties  to  specific  uses.  But  little 
is  known  of  the  effects  produced  by  strains  at  the  imme- 
diate moment  of  heating  and  this  is  the  crucial  question 
connected  with  spot  welding.  Those  who  have  watched 
the  practical  operation  of  making  spot  welds  question 
the  need  of  high  pressures  except  for  making  good  con- 
tact at  the  electrodes,  and  for  holding  the  lapped  pieces 
firmly  together.   A  poor  contact  between  the  pieces  is  a 


^ "  A  Study  of  the  Joining  of  Metals,"  J.  A.  Capp,  General  Electric  Be- 
vieiv,  Dtecember,  1918. 


THEORIES  OF  ELECTRIC  WELDING  181 


desirable  condition  because  a  high  resistance  at  that  point 
locahzes  the  heat.  If  an  excessively  high  pressure  is  not 
required,  or  is  a  disadvantage  to  the  grain  structure  for 
the  right  quality  of  weld,  then  the  designer  of  spot- 
welding  apparatus  would  welcome  the  news,  because  the 
pressures  now  employed  for  heavy  steel  sections  work  a 
hardship  on  the  electrodes. 

There  are  two  theories  of  spot  welding  that  have  re- 
cently come  to  notice,  though  it  should  be  remembered 
while  considering  them  that  it  has  not  been  possible  for 
either  of  the  investigators  to  enter  into  a  consideration  of 
all  the  questions  involved.  The  first  investigation  was 
made  with  rather  medium  material,  about  ^-inch  mild- 
steel  plates,  and  the  deductions  made  were  all  of  a  metal- 
lurgical character.  The  second  was  made  upon  the 
hurried  request  of  the  author  who  submitted  two  samples 
of  spot  welds  in  )^-inch  mild-steel  plate.  The  second 
investigation  reduced  the  matter,  at  least  for  the  pres- 
ent, to  the  ordinary  behavior  of  the  structure  of  steel 
under  the  effects  of  heat.  The  former  theory  for  the 
sake  of  exposition  will  be  called  the  metallurgical  theory 
and  the  latter  the  heat  theory. 

Metallurgical  Theory. — This  theory  was  advanced 
by  its  author  Mr.  E.  E.  Thum,^  in  an  article  entitled 
"  Electric  Welds  "  which  appeared  in  the  September 
15th  issue  of  Chemical  and  Metallurgical  Engineer- 
ing, 1918.  It  is  interesting  not  only  as  a  metallurgical 
observation  but  also  as  one  of  the  first  contributions  to  a 
study  of  the  changes  in  the  structures  of  mild  steel  when 
submitted  simultaneously  to  high  temperatures  and 
great  pressure. 

^  Assoc.  Ed.,  Chemical  and  Metallurgical  Engineering,  N.  Y. 


182 


SPOT  AND  ABC  WELDING 


Mr.  Thum  describes  a  comparative  test  of  the 
strength  of  a  rivet  as  compared  with  that  of  a  spot  weld. 
"  Four  3  X  8-inch  bars  were  cut  from  ^-inch  stock 
structural  steel  plate.  Two  of  these  were  riveted  to- 
gether with  two  %-inch  rivets,  one  driven  1^4  inches 
from  either  end;  while  the  other  pair  were  spot  welded 
at  corresponding  points  with  a  machine  designed  to  give 
a  weld  %  inch  in  diameter.  The  bars  were  then  laid  flat 
on  end  supports,  bent  through  about  45  degrees  by  a 
concentrated  central  load  and  sawed  lengthwise  through- 
out, cutting  through  the  centre  of  the  connection.  .  .  . 
The  bars  riveted  together  slipped  past  one  another, 
shearing  the  rivets,  while  the  bars  welded  together  showed 
absolutely  no  movements  at  the  ends  nor  did  a  micro- 
scopic examination  of  the  weld  show  any  indication  of 
plastic  yielding." 

It  is  to  be  noted  that  small  blow  holes  were  observed 
in  the  weld  which  is  explained  on  the  basis  that  "  the 
sheets  were  taken  from  a  stock  pile  and  no  attempt  made 
to  clean  them  of  rust  or  scale  before  welding.  At  the 
time  of  welding  little  chance  was  given  for  any  extrusion 
of  hot  metal,  owing  to  the  continuous  lateral  support  of 
the  heated  area;  in  this  manner  any  impurities  which 
originally  existed  on  the  surfaces  of  the  plate  would  be 
trapped  and  retained." 

Although  Mr.  Thum  observed  a  peculiar  structure 
to  a  greater  or  less  extent  in  all  the  spot- welded  low- 
carbon-steel  plates,"  which  was  not  noticeable  in  the 
butt  welds  examined,  he  found  this  peculiar  structure 
best  developed  "  near  the  outer  edge  of  the  spot- welded 
structural  plates  "  used  in  the  above  experiment.  The 
structure  referred  to  lies  next  to     spheroidal  mass  at 


THEORIES  OF  ELECTRIC  WELDING  183 


the  centre  of  the  welds  "  and  "  grades  into  the  unaffected 
original  stock  less  abruptly."  The  micrograph  illustrat- 
ing his  article  shows  "  parallel  striations  "  and  foliations 
which  he  believes  suggests  pear  lite  "  which  it  evidently 
cannot  be,  since  the  original  metal  is  ordinary  struc- 
tural steel,  whose  micro-section  gives  the  typical  hypo- 
eutectoid  appearance."  He  next  suggests  the  resem- 
blance to  martensite,  but  puts  this  aside  on  the  basis  that 
"  low-carbon  steel  would  not  be  expected  to  develop  such 
large  quantities  of  martensite  nor  would  martensite  be 
expected  in  separating  zones  of  sorbite  and  pearlite." 
He  then  considers  a  possible  explanation  on  the  assump- 
tion of  annealing  twins,  mechanical  twins,  X-bands  or 
slip  bands,  but  these  conditions  under  which  the  structure 
forms  eliminates  all  of  these  suggestions.  This  leads  to 
the  question  of  the  "  suppression  of  the  carbonaceous 
areas  so  prominent  in  the  centre  of  the  weld  and  in  the 
original  stock." 

After  tracing  in  detail  the  temperature  in  the  various 
ellipsoidal  zones  forming  the  spot  weld  and  clearly  de- 
lineating the  growth  and  subsequent  contraction  of  the 
heated  areas,  he  then  forms  his  opinion  which  follows: 
"  The  austenitic  spheroid,  being  directly  between  the 
dies  of  the  welding  machine,  is  under  considerable  com- 
pressive stress,  but  is  unable  to  flow  any  measurable  dis- 
tance owing  to  its  uniform  side  supports  by  relatively 
rigid  metal.  Extrusion  of  a  fin  as  in  a  flash  weld  is  evi- 
dently impossible,  but  the  highly-stressed  crystals  of 
austenite  develop  their  characteristic  octahedral  cleav- 
age planes  exactly  similar  to  those  accompanying  the 
surface  slip  bands  appearing  in  a  polished  surface  after 
its  underlying  metal  has  been  severely  strained.  On 


184 


SPOT  AND  ARC  WELDING 


cooling  through  the  transformation  range,  the  austenite 
tends  to  precipitate  its  excess  ferrite — each  crystal  re- 
jects the  sorbite  to  its  boundaries,  hence  the  ferrite  tends 
to  gather  along  the  cleavage  planes.  Thus  the  central 
position  of  the  weld  is  largely  of  dark-etching  troostite  or 
sorbite,  but  close  examination  shows  a  well-defined  hair- 
like precipitation  of  the  excess  ferrite  fringing  many  of 
the  allotriomorphic  crystalline  boundaries,  and  numerous 
very  fine,  white,  parallel  striations  crossing  at  60  degrees 
appear  in  one  of  the  dark  areas  near  the  centre  of  the 
original  micrograph.  Very  definite  '  fringes  '  of  larger 
parallel  ferrite  needles  extending  inward  from  the  grain 
boundary  are  seen  near  the  edge  of  the  sorbitic  zone. 

"  Just  outside  the  darker-etching  zone  (in  the  region 
of  eutectiform  structure)  a  peculiar  conjunction  of  pres- 
sure and  temperatvire  occurred.  During  welding  the 
temperature  passed  the  transformation  range,  and  the 
pearlitic  areas  passed  into  austensite.  Migration  of  car- 
bide, to  equalize  the  carbon  contents  of  these  original 
austenitic  crystals,  must  have  been  extraordinarily  rapid. 
The  austenitic  crystals  were  at  the  same  time  fractured 
along  their  octahedral  cleavage  by  the  compressive  stress 
of  the  welding  dies,  exactly  as  indicated  in  the  discussion 
of  the  underlying  dark-etching  areas,  and  on  cooling, 
after  the  electric  current  had  been  interrupted,  each  little 
lamina  bounded  by  the  parallel  cleavage  planes  acted  as 
an  independent  crystal  in  expelling  ferrite  to  its  surfaces. 
Hence  the  ferrite  marks  the  sub-microscopic  cleavage 
planes ;  or  rather,  the  thinnest  plate  of  eutectoid  remains 
at  the  nucleus  of  each  crystalline  lamina.  After  polish- 
ing and  etching,  the  eutectoid  films  etched  dark  as  a 
series  of  straight  lines  crossing  from  boundary  to  bound- 


THEORIES  OF  ELECTRIC  WELDING  185 


ary  of  the  original  crystalline  entity.  Evidently  the 
process  of  extruding  the  ferrite  from  the  original  aus- 
tenite  laminse  was  just  completed  when  the  cooling  of 
the  zone  in  question  prevented  the  further  molecular 
mobility  necessary  for  the  agglomeration  of  the  thin 
plates  into  balls  of  less  superficial  areas,  which  is  the  nor- 
mal appearance  of  low-carbon  steel." 

He  completes  his  interesting  paper  with  a  compari- 
son of  this  "  peculiar  structure  "  to  the  appearance  not 
of  the  Widmanstattian  structure  as  ordinarily  illustrated, 
"  but  the  close-packed  W-bands  ...  on  a  lower 
magnification/'  and  then  states  that,  "  Howe  and  Levy 
observe  the  same  general  appearance  in  over-strained 
and  heated  austenitic  manganese  steel,  caused  by  the 
same  train  of  events,  that  is  to  say,  first  fracturing  the 
original  austenitic  crystals  of  the  quenched  metal  along 
their  cleavage  planes  and  thus  forming  a  multitude  of 
new  crystalline  entities." 

Heat  Theory. — Reference  to  Table  XII,  Chapter 
IV,  giving  the  results  of  tensile  tests  on  thirty  spots  made 
in  one  10-foot  length  of  lapped  S/g-inch  structural-steel 
plates  will  show  that  "  spot  No.  5  "  was  held  for  other 
tests.  The  same  will  be  noted  for  spot  No.  8  "  in  Table 
XIV,  Chapter  IV.  These  samples  were  called  respec- 
tively "  bad  weld  "  and  "  good  weld."  They  were  sent 
to  Mr.  S.  W.  Miller,  proprietor  of  the  Rochester  Weld- 
ing Works,  who  kindly  examined  them  and  prepared 
the  micrographs  (Figs.  1,  2,  and  3). 

The  "  bad  weld,"  No.  5,  in  Table  XII,  lay  between 
spots  4  and  6  which  show  an  ultimate  tensile  of  19,700 
and  28,600,  respectively,  hence  the  name  given  the 
sample.    The  "  good  weld,"  No.  8,  in  Table  XIV,  lay 


186 


SPOT  AND  ARC  WELDING 


between  spots  7  and  9,  which  show  an  ultimate  tensile 
of  64,700  and  52,600,  respectively.  This  was  considered 
practically  "  a  good  weld,"  because  these  tests  were  to 
convince  those  interested  that  uniform  spots  could  be 
made  that  would  exceed  the  strength  of  a  single  rivet 
shear  of  the  size  required  for  the  stock  material  by  ship 
classification  societies.  Lloyd's  for  ^-inch  steel  plate 
would  require  a  %-inch  rivet  which  is  calculated  to  shear 
at  34,100  pounds  per  sqviare  inch.  So  the  bad  weld  " 
was  only  about  half  as  good  as  the  required  rivet  and  the 
"  good  weld  "  was  about  half  again  as  good  as  the  speci- 
fied rivet.  The  mechanical  pressure,  the  current,  and 
voltage,  were  held  approximately  constant;  thus  main- 
taining only  two  variables,  time  and  condition  of  mate- 
rials. As  to  the  latter,  the  slag  and  mill  scale  was 
undisturbed  on  the  lapped  surfaces  of  the  plates,  but  the 
surfaces  next  to  the  electrodes  were  ground  down  with  a 
portable  hand  grinder.  As  the  tables  show,  the  "  bad 
weld  "  was  given  18  seconds  of  both  mechanical  pressure 
and  current,  and  the  "  good  weld  "  was  given  25  seconds 
of  the  same  treatment.  Although  no  chemical  tests  were 
made  to  insure  the  exact  composition  of  the  ^-inch  steel 
plate,  this  material  was  taken  from  stock  which  was  pur- 
chased under  the  specification  requirements  of  the 
American  Society  for  the  Testing  of  Materials,  which 
usually  conforms  to  the  following  analysis: 


Figs.  1  and  2  show  a  section  cut  through  the  spot 
welds  and  magnified  to  double  the  size.    Mr.  Miller's 


Sulphur  .  , 
Carbon  •  .  , 
Phosphorus 
Manganese 


0.04  per  cent. 
0.22  per  cent. 
0.01  per  cent. 
0.41  per  cent. 


THEORIES  OF  ELECTRIC  WELDING  187 


notes  on  Fig.  39  showing  the  "  bad  weld  "  are  as  follows: 
"  Small  defects  in  centre  probably  due  to  shrinkage. 
Grain  at  '  A  '  is  very  coarse,  at  '  B  '  very  fine,  and  at 
'  C  '  coarser  than  original,  but  not  bad.  '  A  '  and  '  B  ' 
are  shown  on  continuous  micrograph  (Fig.  41) ,  but '  C  ' 
is  not  shown.    '  D  '  shows  columnar  grains  due  to  high 


Fig.  39. — Bad  weld  magnified  about  twice.    Small  defects  in  centre  probably  due  to  shrinkage. 
Grain  at  A  very  coarse;  at  B,  very  fine;  at  C,  coarser  than  original,  but  not  bad. 
A  and  B  shown  in  Fig.  41.   D  shows  columnar  grains  due  to  high  temperature  and  rapid  cooling. 
Grain  at  C  equiaxed  due  to  slower  cooling. 


temperature  and  rapid  cooling.  Grains  at '  C  '  equiaxed 
due  to  slower  cooling.  Referring  to  Fig.  40  showing 
'  good  weld,'  the  notations  are  the  same  as  in  Fig.  39. 
'  E  '  crack  at  end  of  weld  probably  due  to  shrinkage. 
In  coin^se  of  time  these  might  be  dangerous.  '  F  '  spot 
of  oxide  in  plate  not  caused  by  welding,  original  defect. 
Columnar  grains  '  D  '  very  clear  in  this  specimen.  Re- 


188 


SPOT  AND  ARC  WELDING 


ferring  to  Fig.  41  this  is  a  continuous  micrograph  at  100 
diameters  taken  from  the  edge  of  '  bad  weld  '  (Fig.  39) 
towards  the  centre.  The  '  good  weld  '  is  the  same  except 
in  degree.   The  union  in  both  welds  is  perfect." 

Mr.  Miller  explains  the  development  of  the  steel 
structure  as  shown  by  these  particular  samples  as  fol- 


FiG.  40. — Good  weld  magnified  twice.  Grain  at  A  very  coarse;  at  B,  very  fine;  at  C,  coarser  than 
original,  but  not  bad.   E,  crack  at  end  of  weld  probably  due  to  shrinkage.    In  course  of  time  these 

might  be  dangerous. 


lows:  "  I  have  spent  considerable  time  in  examining  the 
structure  of  these  welds  under  high  power.  I  was  very 
much  interested  in  examining  them  in  view  of  a  letter 
which  I  received  from  Mr.  Thum,  western  editor  ^  of 
Chemical  and  Metallurgical  Engineering,  in  which  he 
claimed  to  have  found  in  spot  welds  (made,  I  think,  in 
lighter  material)  a  very  peculiar  structure  which  he 

^Now^  Associate  Editor. 


THEORIES  OF  ELECTRIC  WELDING  189 


accounted  for  in  a  very  peculiar  way.  I  have  been  un- 
able to  find  any  evidence  whatever  of  the  structure  to 
which  he  refers,  or  anything  resembling  it. 


Fig.  41. — Continuous  photograph  of  structure  at  100  diameters  from  edge  toward  centre,  taken  from 
bad  weld.   The  good  weld  is  the  same  except  in  degree.   The  union  in  both  welds  is  perfect. 


"  The  changes  in  structure  which  occur  in  spot  welds, 
using  the  two  you  sent  me  as  a  basis  for  my  statements, 
are  only  such  as  would  be  expected  from  the  heat  condi- 


190 


SPOT  AND  ARC  WELDING 


tions  under  which  the  work  is  done.  When  the  plates  are 
just  touching,  the  heavy  current  heats  up  the  spots  that 
are  in  contact,  and  the  temperature  becomes  very  high 
locally,  due  to  the  resistance.  The  amount  and  extent 
of  this  heat  will  vary,  of  course,  between  different  welds, 
but  not  seriously.  The  heat  becomes  less  as  the  outside 
of  the  plate  is  approached  because  of  the  conductivity  of 
the  plate  and  the  cooling  effect  of  the  cooler  outside 
layers.  There  are  certain  well-defined  temperatures  of 
steel  of  any  given  carbon  content  at  which  changes  in 
structure  take  place  when  heated,  these  resultant  struc- 
tures depending  on  both  the  amount  and  time  of  appli- 
cation of  the  heat. 

"  In  the  centre  of  a  spot  weld  the  temperature  is  very 
high,  probably  near  the  fusing  point.  The  cooling  is 
rapid  and  the  result  is  a  structure  in  the  centre  of  the 
spot  weld  inside  of  the  ellipse  in  which  the  grains  are 
columnar  and  perpendicular  to  the  outline  of  the  ellipse. 
This  is  just  what  occurs  in  electric  arc  welds  and  in  the 
cooling  of  steel  castings  in  molds.  In  the  case  of  a  weld, 
the  long  axes  of  the  columnar  grains  are  perpendicular 
to  the  sides  of  the  Vs.  In  a  casting,  they  are  perpen- 
dicular to  the  sides  of  the  mold.  Further  inside  of  the 
ellipse  the  grains  are  coarse,  due  to  the  very  high  tem- 
perature. Just  outside  of  the  ellipse  the  temperature 
has  not  been  high  enough  to  permit  of  the  formation  of 
columnar  grains,  but  the  grains  are  coarse;  and  due  to 
the  comparatively  high  temperature  and  rapid  cooling, 
pearlite  has  not  had  time  to  form,  so  that  the  structure  is 
confused  and  the  ferrite  and  cementite  are  rather 
indiscriminately  mixed. 

"  Still  further  out  in  the  dark  zone  the  heat  has  been 


THEORIES  OF  ELECTRIC  WELDING  191 


high  enough  and  the  coohng  rapid  enough  to  produce 
sorbite  in  the  grains,  surrounded  by  a  film  of  ferrite. 
This  is  also  a  typical  structure  in  electric  and  oxy- 
acetylene  welds,  and  is  simply  another  degree  in  the 
transition  stage  from  melted  metal  to  normal  steel.  The 
temperature  in  this  sorbitic  zone  has  been  so  high  that 
the  grains  have  had  time  to  grow.  They  are,  therefore, 
very  large,  although  equiaxed  and  not  columnar. 

"  Just  beyond  this  zone  is  one  in  which  the  tempera- 
ture has  been  just  above  the  upper  critical  point,  the 
Ac3  point.  This  temperature  was  sufficient  to  refine  the 
grain  as  much  as  can  be  done  by  heat  treatment  alone. 
This  also  is  characteristic  of  electric  and  oxy-acetylene 
welds.  Outside  of  this  last  zone  the  material  gradually 
changes  to  that  of  the  original  metal  unaltered  by  the 
heat.  As  stated  before,  I  can  see  no  difference  between 
the  structures  in  and  around  spot  welds  and  those  in  oxy- 
acetylene  and  electric  welds  except  in  degree. 

"It  seems  to  me  that  these  statements  are  entirely  in 
accordance  with  the  theory  of  heating,  and  I  cannot  find 
any  evidence  so  far  that  the  pressure  has  anything  to  do 
with  the  structure,  although  it  is  possible,  as  stated  in  my 
former  letter,  that  it  may  have  some  effect.  This,  how- 
ever, would  require  considerable  investigation  before 
drawing  conclusions.  I  think  it  can  be  safely  said  that 
there  is  no  reason  to  be  apprehensive  of  the  strength  of 
spot  welds ;  and  the  two  that  you  sent  me  appear  to  be  of 
excellent  quality,  although  probably  the  second  one  is 
somewhat  better  than  the  first."  ^ 

It  is  to  be  expected  that  these  two  theories  of  spot 
welding  will  lead  to  further  inquiry  into  the  nature  of 

*  Personal  letter  from  S.  M.  Miller,  dated  May  7,  1919. 


192 


SPOT  AND  ARC  WELDING 


the  reaction  which  takes  place  in  the  steel  structure.  The 
important  practical  deduction  is  clear  that  the  process  is 
a  sound  one  for  joining  heavy  structural  members. 

Practical  Aspects. — In  this  connection  there  were  a 
few  points  observed  during  the  demonstration  at  Potts- 
town  that  may  aid  in  dispelling  certain  preconceived 
notions.  On  the  other  hand,  they  may  lead  to  more 
interesting  doubt  which  often  ends  in  greater  benefit  to 
such  a  process. 

The  first  point  had  to  do  with  the  size  of  spot  mdi- 
cated  after  tensile  pulling.  It  was  generally  held  that 
the  size  of  spot  had  a  great  deal  to  do  with  its  physical 
strength.  In  the  earliest  tests  attempts  were  made  to 
compute  the  diameter  of  the  spot  and  reduce  the  ulti- 
mate tensile  strength  to  pounds  per  square  inch  of  the 
observed  spot.  This  was  reasonable  in  view  of  the  method 
pursued  in  the  case  of  a  riveted  joint,  but  the  punching 
of  the  holes  for  riveting  had  removed  good  metal  usually 
replaced  by  one  of  poorer  quality.  In  spot  welding  the 
original  metals  are  there,  but  changed  in  structure,  and 
logically  the  union  of  the  metals  could  be  made  continu- 
ous by  the  proximity  of  the  spot  or  to  the  overlapping  of 
same.  It  was  conceded  during  these  tests  that  the  diam- 
eter of  the  spot  was  merely  an  estimation  depending 
upon  the  observer.  Allowing  liberally  for  this  inaccuracy 
it  will  be  seen  from  the  tabulations  in  Chapter  IV  that 
the  diameters  of  spots  so  recorded  do  not  consistently 
indicate  the  strength  characteristics  of  the  union.  The 
data  of  Lloyd's  tests  (Tables  XV,  XVI,  XVII,  and 
XVIII)  in  this  respect  gives  composite  estimates  made 
by  several  observers.  The  difficulty  of  judgment  of  the 
spot  size  is  complicated  by  the  change  in  form  of  the 


THEORIES  OF  ELECTRIC  WELDING  193 


spot.  As  will  be  seen  by  comparing  Figs.  1  and  2  the 
impression  is  at  times  of  a  circle  and  then  of  an  ellipse. 
Further,  the  effect  of  the  cooling  process  makes  for  more 
confusion  in  determining  the  ring  or  boundary  of  the 
adhesion.  It  is  possible,  also,  that  these  lines  of  demarka- 
tion  may  be  attributed  to  the  surface  strains  occasioned 
by  tensile  pulling.  A  good  example  of  the  range  of 
ultimate  tensile  for  constant  observed  size  of  spot  is  seen 
in  Table  XV,  Chapter  IV.  From  spot  No.  7  to  spot 
No.  20  the  data  gives  the  spot  diameter  as  11/16  inch. 
The  first  four  of  these  spots  were  made  in  16  seconds, 
the  next  ten  were  made  in  12  seconds.  The  ultimate  ten-  - 
sile  ranged  from  18,600  pounds  to  12,200  pounds. 

The  next  point  of  interest,  and  often  of  surprise  to 
those  who  had  not  seen  it,  was  the  fracturing  of  the  stock 
material  and  the  complete  adherence  of  the  union  at  the 
spot.  This  is  remarkable  in  the  ^-inch  plate  samples  as 
shown  by  the  results  in  Table  XVII,  Chapter  IV.  The 
samples  were  visibly  twisted  in  the  Olsen  testing  ma- 
chine and  in  the  majority  of  cases  the  yielding  of  the 
material  surrounding  the  spot  was  clearly  observable, 
taking  many  seconds  before  complete  rupture.  In  some 
instances  it  was  necessary  to  wait  quite  a  time,  and  in 
others  to  subject  the  test  piece  to  further  loading.  The 
implication  is  not  unwarranted  that  the  ultimate  rupture 
is  more  than  safely  removed  from  the  initial  yield  point. 
This  statement  should  not  be  confused  with  the  impres- 
sion so  often  concluded  that,  because  the  stock  material 
fractures  without  the  region  of  the  weld,  that  the  weld 
is  better  than  the  stock  material.  As  a  matter  of  inves- 
tigation this  may  be  a  serious  defect  of  the  process.  The 
important  consideration  is  how  far  the  application  of 

13 


194 


SPOT  AND  ARC  WELDING 


heat  and  pressure  may  be  employed  so  as  to  preserve 
the  integrity  of  the  original  structure  and  yet  obtain  a 
tensile  strength  sufficient  for  practical  purposes.  Table 
XVII,  Chapter  IV,  shows  a  much  higher  uniform  tensile 
strength  of  spot  welds  than  is  required  to  compete  with 
the  rivets  required  for  a  similar  jointure. 

The  third  and  last  point  observed  has  to  do  with  the 
heat  conductivity  of  the  plate  material  and  its  relation  to 
electric  conductivity.  Unfortunately,  this  observation 
was  most  clearly  noticed  in  the  last  series  of  tests  which 
could  not  be  extended  with  sufficient  fulness  to  make 
definite  conclusions.  In  the  earlier  tests  it  was  noticed 
that  the  end  spots  in  a  continuous  seam,  if  given  an  equal 
time  with  the  intermediate  spots,  would  show  an  increased 
ultimate  tensile.  If  the  end  spot  were  given  slightly 
more  time,  the  ultimate  tensile  was  very  much  increased ; 
and  in  many  cases,  if  the  time  were  less  on  the  end  spots, 
the  ultimate  tensile  was  as  good  or  better.  This  action 
can  be  noted  by  reference  to  the  tabulations  in  Chapter 
IV.  The  first  samples  made  with  the  object  of  adjust- 
ing the  machine  were  two  narrow  strips  of  steel  with  a 
single  spot.  Undoubtedly,  the  results  from  this  test 
which  fixed  the  adjustments  and  constants  used  in  weld- 
ing the  ship's  floors  gave  a  wrong  assumption  which  the 
uniformity  tests  afterward  corrected.  There  can  be  no 
doubt  that  in  making  successive  spot  welds,  either  in 
single,  double,  or  triple  rows,  the  temperature  varia- 
tions in  the  stock  material  bear  a  close  relation  to  the 
resultant  tensile  strength  of  any  given  spot.  It  is  sug- 
gested that,  in  line  with  the  heat  cycle  of  each  individual 
spot,  the  residual  or  recuperating  structure  of  the  stock 
material  may  interfere  with  its  natural  changes.  Con- 


THEORIES  OF  ELECTRIC  WELDING  195 


versely,  the  heat  cycle  of  an  individual  spot  may,  through 
the  action  of  conductivity,  or  convectivity,  affect  the  spots 
already  made.  During  the  tests  it  often  happened  that 
work  was  interrupted  and  seams  were  left  to  cool  all 
night  in  a  rather  cold  shop,  but  continuation  of  the  work 
did  not  indicate  that  such  interruptions  were  detrimental 
to  uniformity. 

In  the  last  practical  tests  two  and  three  rows  of  spots 
were  made  in  j4-inch  steel  plates.  The  first  samples  were 
made  by  continuous  spots  first  on  one  row  and  then  on 
the  next  row,  and  the  time  was  held  constant  for  all  spots. 
As  the  uniformity  tests  for  this  thickness  of  material  in- 
dicated good  results  at  15  seconds,  this  time  interval  was 
adopted.  The  tensile  pulling  of  all  these  samples  were 
far  below  expectations  and  a  second  attempt  was 
immediately  made. 

Fig.  42  shows  the  order  in  which  the  spots  were  now 
made.  It  is  to  be  noted  that  this  order  of  spot  put  them 
in  line  with  the  tensile  pulling.  The  time  intervals  were 
varied,  i.e.,  in  the  two-row  sample  the  end  spots  were 
given  15  seconds  and  the  intermediate  spots  20  to  30 
seconds;  in  the  three-row  sample  the  end  spots  were 
given  20  seconds  and  the  intermediate  25  to  30  seconds. 
Fig.  42  attempts  roughly  to  show  the  relative  size  of 
spots  as  observed  on  the  samples  after  tensile  pulUng. 
The  Roman  numerals  are  the  strips  as  cut  for  the  pulling 
tests.  Nos.  I  and  VI  of  the  two-row  and  Nos.  I  and  VI 
of  the  three-row  samples,  though  given  reduced  time, 
exceeded,  except  No.  V  of  the  two-row  sample,  all  the 
intermediate  spots. 

As  speculation  is  only  possible,  it  is  assumed  that,  as 
the  metal  is  locally  heated  by  the  electric  resistance 


196 


SPOT  AND  ARC  WELDmO 


which  increases  with  the  temperature,  the  surround- 
ing metal  tends  to  conduct  away  the  heat.  The  end 
spots  would  have  the  advantage  of  no  plate  material  or, 


COMPARATIVE  SIZE  OF  SPOTS -2  SPOTS  S" LAP 


COMPARATIVE  SIZE  OF  SPOTS -3  SPOTS- 9" LAP 

Fig.  42. — Comparative  size  of  spots — 3  spots  =  9"  lap. 


at  least,  a  very  small  area  of  conductance  on  one  side  and 
a  large  area  on  the  other  side.  The  intermediate  spots 
would  be  in  varying  degrees  circumscribed  in  this  re- 
spect. It  will  be  noticed  in  Fig.  42  that  the  No.  II  strip, 
which  is  a  combination  of  spots  3  and  4,  is  not  compa- 


I 


THEORIES  OF  ELECTRIC  WELDING  197 


rable  in  tensile  strength  to  strip  No.  V  which  is  a  com- 
bination of  spots  Nos.  9  and  10.  These  latter  spots 
being  made  after  the  entire  piece  of  material  was  well 
heated.  It  is  observed  in  continuous  spot  welding  that 
the  spot  adjacent  to  the  one  being  made  glows  to  cherry- 
red  heat.  Further,  though  not  so  common,  a  number  of 
spots  in  the  vicinity  of  the  weld  being  made  glow  at  vary- 
ing degrees.  This  observation  would  indicate  that  the 
metal  of  the  plate  is  conducting  some  of  the  electrical 
energy  from  the  electrode  and  doubtless  aids  in  the  results 
of  decreasing  ultimate  tensile  as  shown  by  these  tests. 

Arc  Welding. — Whereas  the  theories  of  spot  weld- 
mg  are  scant,  those  for  metallic  arc  welding  are  very 
numerous.  It  is  not  to  be  inferred  that  numbers  in  this 
case  give  finality  to  conclusions;  on  the  contrary,  the 
light  is  very  dim  in  the  region  of  the  weld,  and  besides 
the  phenomenon  of  the  arc  leads  to  various  aspects  of 
the  problem. 

Metallurgical  Views. — The  deposit  from  the  metallic- 
arc  electrode  is  defined  and  treated  as  an  unannealed 
steel  casting.  In  the  making  of  this  casting  the  stock 
materials  joined  play  an  important  role,  because  the  arc 
must  fuse  the  adjacent  metal  and  mix  with  a  portion  of 
it  to  form  the  weld.  Accepted  as  a  casting,  the  efforts 
of  the  metallographists  have  been  to  discover  why  the 
structure  displays  brittleness  with  good  tensile  strength 
and  what  means  may  be  taken  to  make  this  casting  more 
ductile.  These  are  questions  which  when  fully  answered 
will  standardize  materials  and  apparatus,  and  also  re- 
lieve the  operator  from  much  responsibility. 

With  the  aid  of  the  microscope,  investigators  have 
found,  upon  the  examination  of  the  weld,  whether  by 


198 


SPOT  AND  ARC  WELDING 


fracture  or  by  cutting,  a  structure  which  contains  a  large 
number  of  lines  or  plates.  The  determination  of  the 
composition  of  these  plates  has  brought  with  it  differ- 
ences of  opinion  and  modification  of  views  which  make 
conclusions  impossible.  One  specialist  finds  these  plates 
at  the  grain  boundaries  as  well  as  in  the  grains,  and  fur- 
ther observations  have  caused  him  to  believe  that  the 
grains  are  bounded  by  thin  films  which  are  sufficiently 
tenacious  to  preserve  a  high  tensile  strength  in  the  weld, 
yet  will  rupture  under  shock  or  alternating  stress.  His 
observations  affirm  that  crystallization  cannot  take  place 
through  these  films,  but  he  is  not  ready  to  state  what  the 
composition  of  the  films  may  be.  He  suggests  the  im- 
probability of  their  being  cementite  in  the  case  of  metallic- 
electrode  welds,  "  as  the  carbon  is  almost  entirely  burnt 
out,"  ^  but  he  allows  the  possibility  of  iron  oxide,  or 
nitride  of  iron. 

Another  expert  concludes  that  the  plates  or  lines 
"  are  not  cementite,  or  martensite,  or  any  similar  carbide 
product,  but  most  probably  nitride  of  iron."  ^  This  con- 
clusion was  arrived  at  after  careful  investigation  of  a 
specimen  in  which  the  deposited  metal  was  analyzed  and 
showed  a  carbon  content  of  0.04  per  cent,  carbon. 

Still  another  specialist  calls  these  plates  Nitrogen 
lines,"  showing  "  the  presence  of  a  considerable  percent- 
age of  nitrogen,  but  their  absence  does  not  always  mean 
that  nitrogen  is  not  present."^    He  states  further: 

^"  Path  of  Rupture  in  Steel  Fusion  Welds,"  S.  W.  Miller,  Trans.  Amer. 
Inst.  Mining  Engineers,  February,  1919. 

^ "  Micro-structure  of  Iron  Deposited  by  Electric  Arc  Welding,"  G.  F. 
Comstock,  A  mer,  Inst.  j\linin(f  Engrs.,  Feb.,  1919, 

'  "  The  Metallurgy  of  the  Arc  Weld,"  W.  E.  Rudder,  General  Electric 
Review,  December,  1918. 


THEORIES  OF  ELECTRIC  WELDING  199 


"  Nitrogen  is  one  of  the  most  effective  elements  for  mak- 
ing steel  brittle.  As  little  as  0.06  per  cent,  will  reduce 
the  elongation  on  a  0.2-per-cent.  carbon  steel  from  28 
per  cent,  to  5  per  cent.  It  is  contained  in  regular  steel 
only  in  very  small  amounts,  varying  from  0.02  per  cent, 
in  Bessemer  steel  to  0.005  per  cent,  in  open-hearth. 
Under  ordinary  conditions  of  fusion,  nitrogen  has  little 
effect  upon  iron,  but  under  the  conditions  of  the  electric 
arc  the  nitrogen  becomes  more  active.  This  is  probably 
due  to  the  formation  and  decomposition  of  nitrogen- 
oxygen  compounds  with  a  consequent  liberation  of  active 
atomic  nitrogen.  The  fact  that  these  lines  do  appear  in 
welds  made  in  nitrogen  gas  alone  suggest  that  the  oxy- 
gen need  not  be  present,  the  nitrogen  molecule  being 
split  up  by  the  arc  stream,  or  perhaps  the  iron  vapor 
combines  directly  with  the  nitrogen.  There  is  some  evi- 
dence that  it  does." 

This  opinion  leads  to  the  subject  of  occluded  gases, 
i.e.,  gases  that  are  absorbed  by  steel.  Theoretically,  these 
occluded  gases  would  play  some  part  in  the  reactions 
that  take  place  under  the  intense  heat  of  the  arc  vapor, 
the  temperature  changes  following  the  passage  of  the 
arc,  and  the  cooling  effects  produced  by  the  conductivity 
of  the  mass  of  steel  acted  upon.  For  this  reason  the  arc 
operator  learns  to  localize  his  arc  and  thus  prevent  the 
stock  materials  from  attaining  a  high  degree  of  heat. 
Such  a  condition,  if  permitted,  causes  too  slow  cooling 
which  results  in  a  coarse  grain  and  probably  traps  gases 
which  react  to  cause  brittleness  in  the  finished  weld.  The 
field  of  research  for  the  comprehension  of  the  nature 
and  action  of  occluded  gases  is  as  important  as  any  of 
the  other  investigations  tending  to  a  solution  of  the 


200 


SPOT  AND  ARC  WELDING 


questions  which  now  cloud  a  complete  knowledge  of 
this  process. 

An  interesting  set  of  experiments  with  the  object  of 
analyzing  and  measuring  the  occluded  gases  in  iron  alloys 
was  performed  by  Gellert  Alleman,  professor  of  chem- 
istry, Swarthmore  College,  Pa.^  The  results  of  this  in- 
vestigation are  so  closely  akin  to  the  theories  of  arc 
welding  that  it  is  recommended  that  those  desiring  fur- 
ther information  on  this  subject  carefully  consider  them. 
It  is  not  possible  to  quote  the  whole  article,  but  the  con- 
clusions that  have  a  bearing  upon  the  metallurgy  of  arc 
welds  are  as  follows:  (3)  It  appears  that  the  gases  are 
evolved  in  the  following  order:  Hydrogen  is  most 
readily  set  free,  carbon  monoxide  comes  next,  and  nitro- 
gen seems  to  be  held  most  tenaciously. 

"  (.4)  Whether  oxygen  is  the  result  of  the  decomposi- 
tion of  various  oxides  of  iron  or  the  disassociation  of  car- 
bon monoxide  or  carbon  dioxide  has  not  been  determined. 

(5)  We  have  shown  that  ferrous  alloys  may  occlude 
relatively  large  volumes  of  gases — in  some  cases  equal  to 
about  two  hundred  times  the  volume  of  the  metal. 

''(6)  We  suggest  that  in  addition  to  the  ordinary 
functions  of  metals  like  aluminum,  tungsten,  chromium, 
manganese,  titanium,  silicon,  etc.,  when  placed  in  fer- 
rous alloys,  these  elements  may  act  as  a  catalytic  agent ; 
and  either  prevent  the  occlusion  of  large  quantities  of 
gases  or  aid  in  the  elimination  of  such  gases  at  lower 
temperatures  than  would  ordinarily  take  place. 

(7)  We  have  shown  that  the  removal  of  gases  from 
ferrous  alloys  markedly  changes  the  microstructure  and 
increases  the  density  of  the  alloy." 

^  "  Occluded  Gases  in  Ferrous  Alloys,"  Gellert  Alleman  and  C.  J.  Dar- 
lington, Journal  of  The  Franklin  Institute,  1918. 


THEORIES  OF  ELECTRIC  WELDING  201 


Arc  Characteristics. — "The  arc  is  the  welder's  essen- 
tial tool.  It  functions  to  transform  electrical  into  highly 
concentrated  thermal  energy.  At  the  terminals  this 
energy  serves  to  melt  the  parent  and  filling  metals :  in 
the  stream  it  stabilizes  the  arc  and  surrounds  the  fluid 
pencil  metal  with  a  protecting  mantle  of  hot  inert  gases, 
usually  oxide.  A  short  arc  length  obviously  assures 
greater  protection  to  the  transferred  metal  than  a  long 
arc,  as  the  path  traversed  by  the  incandescent  metal  is 
shorter  and  the  liability  of  convection  currents  disturb- 
ing the  protecting  envelope  less. 

"  The  mechanism  producing  crater  formation  and 
transference  of  metal  from  the  pencil  electrode  to  the 
parent  metal  has  not  been  definitely  isolated.  However, 
it  appears  reasonable  to  assume  that  the  propulsive  force 
projecting  the  filling  metal  across  the  arc  is  largely  ob- 
tained from  the  rapid  expansion  of  occluded  gases  and 
vaporized  metal,  the  impact  of  the  conveyed  gas,  vapor, 
and  liquid  on  the  molten  surface  of  the  parent  metal 
producing  the  familiar  crater. 

"It  is  well  known  that  all  metals  absorb  gas,  and 
that  the  quantity  of  gas  occluded  varies  with  the  char- 
acteristics, preparation,  and  exposure  of  the  metals. 
Iron  has  been  analyzed  containing,  at  atmospheric  tem- 
perature, as  much  as  50  volumes  of  gas.  Upon  forming 
an  arc  the  extreme  end  of  the  pencil  electrode  is  partly 
liquefied  and  partly  vaporized  and  then  conveyed  across 
the  arc  stream.  The  concentration  of  energy  at  this 
terminal,  approximating  1500  watts  for  a  150-ampere 
welding  current,  produces  a  rapid  increase  in  tempera- 
ture, and  therefore  a  corresponding  increase  in  the  ex- 
pansion of  the  metallic  liquid  and  vapor  and  absorbed 


202 


SPOT  AND  ARC  WELDING 


gas.  This  expansion  would  tend  to  follow  the  path  of 
least  resistance  which  extends  through  the  arc  terminal 
and  into  the  arc  stream.  Its  effect  wovild  be  to  produce 
a  metallic  blast.  The  force  of  this  stream  has  been  ob- 
served to  vary  with  change  in  electrode  analyses,  char- 
acter of  occluded  gas,  current  density,  arc  length,  and 
the  use  of  direct  or  alternating  current.  An  additional 
expansive  force  is  probably  secured  by  the  union  of  elec- 
trode materials  with  occluded  and  atmospheric  gases. 
However,  as  the  temperatures  in  the  arc  stream  are  too 
high  to  permit  the  existence  of  such  compounds  their 
formation  must  occur  in  the  surrounding  envelope  with 
the  result  that  the  force  developed  is  partly  absorbed  in 
scattering  hot  metal. 

The  metallic  blast  is  of  particular  interest  because 
it  appears  to  be  the  basis  for  overhead  welding.  How- 
ever, to  properly  utilize  this  phenomena  it  is  necessary 
for  the  welder  to  maintain  obviously  a  short  arc  and  to 
adjust  welding  conditions  so  that  the  electrode  end  im- 
mediately below  the  arc  terminal  remains  comparatively 
cool.  If  a  globule  of  molten  solder  is  dropped  on  the 
inclined  surface  of  a  cold  plate,  it  will  run  off  at  a  slower 
rate  than  if  it  strikes  an  inclined  hot  surface,  due  to  the 
difference  in  strength  of  the  film  produced  by  both  sur- 
face tension  and  the  congealing  of  the  metal.  Similarly, 
if  the  electrode  end  is  maintained  at  a  high  temperature, 
the  molten  metal  will  run  down  the  side  of  the  electrode, 
thereby  greatly  increasing  the  difficulty  of  utilizing  the 
vapor  blast.  Such  heating  of  the  electrode  also  causes 
leakage  of  occluded  gas  through  the  hot  wall  with  con- 
sequent diminution  of  the  force  produced  by  gas  expan- 
sion at  the  arc  terminal. 


THEORIES  OF  ELECTRIC  WELDING  203 


"  Excessive  electrode  temperatures  are  usually  ob- 
tained as  a  result  of  repeated  attempts  to  start  the  arc. 
When  a  nmnber  of  false  starts  are  made  increased  heating 
results,  due  to  the  greater  current  flowing  with  the  arc 
short-circuited.  If  the  operator  develops  the  necessary 
skill  to  deposit  metal  after  but  a  single  start,  the  pencil 
electrode  end  will  remain  quite  cool,  facilitating  thereby 
the  continued  transference  of  metals  to  an  overhead  weld. 
Other  aids  to  the  maintenance  of  the  proper  electrode 
temperature  are : 

''1.  Use  of  a  lower  current  density  than  that  em- 
ployed for  flat  or  downward  deposition. 

"2.  Use  of  an  electrode  having  a  melting  point 
higher  than  that  of  the  parent  metal. 

"  3.  Use  of  a  direct-current  supply  circuit  having 
such  characteristics  that  the  arc  short-circuit  current 
does  not  exceed  greatly  the  operating  current. 

"  4.  Use  of  a  thin  coating  on  electrode  to  facilitate 
starting  the  arc."  ^ 

Physical  Views. — In  general  the  theory  is  accepted 
that  after  the  metallic  arc  is  struck  a  vaporous  stream  of 
metal  from  the  electrode  is  formed.  Surrounding  this 
vaporous  stream  is  a  clearly-visible  flame  indicative  of 
ordinary  combustion  and  hence  considered  "  a  flame  of 
oxides."  An  observer  working  upon  the  problems  of 
automatic  arc  welding  holds  this  theory:  "  As  the  result 
of  thousands  of  observations  of  welds  produced  auto- 
matically (wherein  the  personal  equation  is  entirely 
eliminated) ,  the  writer    inclines  towards  the  theory  that 

^  Comimunicated  to  the  Author  by  O.  H.  Escholz,  Oct^  4,  1919.  See 
Electrical  World,  Sept.  27,  1919,  et  seq. 

"  Discussion  on  Welding  Mild  Steel,"  Harry  D.  Morton,  Transactions 
American  Soc.  Mining  Engineers,  1919. 


204 


SPOT  AND  ARC  WELDING 


the  molten  electrode  material  passes  through  the  arc  in 
the  form  of  globules,  and  that  where  ^-inch  electrode 
material  is  employed  with  a  current  of  about  150  amperes 
these  globules  are  deposited  at  the  rate  of  approximately 
two  per  second.  The  passage  through  the  arc  of  each 
globule  apparently  constitutes  a  specific  cause  of  insta- 
bility in  addition  to  those  existent  with  slowly-consumed 
electrodes.  This  hypothesis  seems  to  be  borne  out  by 
ammeter  records,  together  with  the  fact  that  the  elec- 
trode fuses  at  the  rate  of  about  0.2  inch  per  second. 
Moreover,  the  globules  appear  to  be  approximately 
equal  in  volume  to  a  piece  of  wire  0.125  inch  in  diameter 
and  0.1  inch  long." 

In  the  same  article  this  last  observer  gives  this  vivid 
picture  of  the  arc  at  work:  ''What  seems  to  occur  is 
that  the  molten  metal  in  the  crater  is  in  a  state  of  violent 
surging,  suggestive  of  a  small  lake  lashed  by  a  terrific 
storm.  The  waves  are  dashed  against  the  sides  of  the 
crater,  where  the  molten  metal  of  which  they  are  com- 
posed quickly  solidifies.  The  surgings  do  not  seem  to 
synchronize  with,  nor  to  be  caused  by,  the  falling  of  the 
globules  of  molten  metal  into  the  crater,  but  seem  rather 
to  be  continuous.  They  give  the  impression  that  the 
molten  metal  is  subjected  to  an  action  arising  from  the 
disturbance  of  some  powerful  force  associated  with  the 
arc — such,  for  instance,  as  might  result  from  the  violent 
distortion  of  a  strong  magnetic  field.  Altogether,  the 
crater  phenomena  are  very  impressive;  and  the  writer 
hopes  ere  long  to  be  able  to  have  motion  pictures  made 
which,  when  enlarged,  should  not  only  afford  material 
for  the  most  fascinating  study,  but  also  throw  light  upon 
some  of  the  mysterious  happenings  in  the  arc." 


THEORIES  OF  ELECTRIC  WELDING  205 


Other  opinions  have  to  do  with  a  study  of  the  spec- 
trum of  the  metalhc  arc  in  which  department  of  research 
apparently  httle  work  has  been  done.  Such  investiga- 
tions would  require  special  apparatus  whereby  the  arc 
would  be  not  only  observed  under  varying  electrical  con- 
ditions, but  also  recorded  in  small  increments  of  time. 
Follow^ing  one  set  of  electrodes  and  stock  materials  many 
combinations  would  need  examination  before  a  complete 
spectroscopic  theory  could  be  approached. 

Electrical  Views. — Much  of  the  electrical  theory  is 
concerned  with  voltage  drop.  It  has  been  well  stated 
that  "  up  to  the  present  no  satisfactory  proof  of  any 
theory  has  been  put  forward.  It  is  by  some  ascribed  to 
a  back  e.m.f.  produced  at  the  point  of  volatilization  of  the 
carbon  and  by  others  to  the  energy  absorption  required 
by  this  volatilization."  In  view  of  this  opinion,  it  is  in- 
teresting to  note  the  experience  of  a  careful  observer  as 
to  the  action  of  the  welding  voltage.  The  results  of  his 
investigations  are  given  in  full : 

"  After  careful  compilation  of  about  five-hundred 
readings  of  voltage  across  the  arc  and  current  through 
it,  I  was  forced  to  the  conclusion  that  the  current  does 
not  affect  the  voltage  enough  for  an  ordinary  meter  to 
notice  it.  With  an  oscillograph  the  rapid  variations  in 
voltage  due  to  changes  in  the  current  can  be  traced ;  but 
the  voltage  as  shown  by  an  ordinary  meter,  no  matter 
how  delicate,  is  constant  for  any  set  of  given  conditions. 
The  conditions  which  do  change  the  volts  across  the  arc 
are :  First,  length  of  arc ;  second,  type  of  electrode ;  third, 
gases  in  the  arc  such  as  would  appear  from  coating  on 
the  electrode  or  flvix  used  on  the  job. 

"  There  is  a  voltage  below  which  an  arc  cannot  be 


206 


SPOT  AND  ARC  WELDING 


held.  And  without  starting  an  argument,  as  to  whether 
this  is  a  counter  e.m.f.,  a  C.  R.  drop,  or  a  combination 
of  the  two,  we  are  calhng  it  a  minimum  arc  voltage. 
This  lies  between  10  and  11  volts.  There  is  added  to 
that  always  a  constant  drop,  depending  on  one  of  the 
three  conditions  named  above,  and  this  drop  varies  from 
one  to  two  volts  in  bare  wire  at  ordinary  welding  cur- 
rents to  15  to  20  volts  for  heavily-coated  wires.  There 
is  the  added  resultant  due  to  the  average  value  of  the 
superimposed  guardian,  or  puncture  voltages,  the  peaks 
of  which  are  shown  only  on  the  oscillograph,  but  the 
average  value,  of  course,  adds  to  the  other  two,  making 
the  voltage  across  the  arc  as  we  have  found  it  to  be  as 
follows:  For  bare  wire  from  11  or  12  volts  to  22  volts, 
the  lower  value  being  an  inhumanly  steady  operator 
holding  the  closest  arc  possible  with  a  wire  that  has  no 
carbon  content  nor  any  covering  or  flux.  The  other  end 
of  the  scale  is  the  carbon  arc,  about  which  much  has  been 
published,  which  voltage  varies  from  40  to  55.  The 
highest  metallic-arc  voltage  is  that  of  a  very  heavily- 
coated  electrode,  such  as  the  English  Quasi- Arc.  The 
voltage  across  this  varies  from  27  to  40.  The  voltage 
across  a  completely-coated  gaseous-flux  electrode  is  from 
22  to  35.  The  voltage  across  a  half -coated  electrode 
varies  from  15  to  30,  the  variations  being  as  aforestated, 
the  sum  of  the  variable-length  voltage  to  the  constant 
ordinary  resistance  drop  and  the  necessary  voltage.  The 
only  voltage  that  is  variable  is  that  due  to  the  man's  hand 
in  holding  different  lengths  of  arc. 

"  I  think  it  is  admitted  by  now  that  the  short  arc  is 
desirable;  in  fact,  a  short  arc  is  absolutely  necessary  for 
good  work.   With  a  short  arc  there  is  less  chance  of  the 


THEORIES  OF  ELECTRIC  WELDING  207 


metal  being  oxidized,  less  chance  that  it  will  fall  on  cold 
work,  less  chance  that  nitrogen  will  be  raised  to  such  a 
temperature  that  it  will  combine  with  carbon  and  steel 
to  form  harmful  compounds,  and  less  chance  of  oxida- 
tion. And,  a  point  that  has  probably  not  been  mentioned 
before,  the  total  heat  is  kept  within  reasonable  control; 
namely,  every  welder  knows  that  with  a  short  arc  he  has 
the  metal  under  control,  but  with  a  long  arc  the  heat  is 
raised  by  the  voltage  having  risen  across  it.  If  there  is 
any  decrease  in  the  current  and  the  temperature,  it  rises 
until  the  steel  is  '  wild.'  And,  whereas  the  transition 
from  a  short  arc  to  a  long  arc  is  easy,  the  transition 
backwards  is  very  hard,  and  the  tendency  is,  once  having 
started  the  long  arc,  to  hold  it  at  least  until  the  end  of  the 
electrode.  Unfortunately,  when  no  check  is  made  on  the 
quality  of  the  metal  deposited,  the  long  arc  being  easier 
held — depositing  the  metal  faster — is  used;  and  in  some 
rare  cases,  such  as  filling  in  castings,  where  the  mass  of 
metal  is  great  enough  to  satisfactorily  dispose  of  the  in- 
creased rate  of  heat,  it  can  be  used  to  advantage. 

"  There  has  been  much  promotion  of  constant- 
current  apparatus,  and  equal  promotion  of  constant  volt- 
age, but  it  can  hardly  be  denied  that  a  constant  rate  of 
heat  is  what  is  desired.  For  a  necessary  change  in  length 
of  arc  due  to  various  physical  imperfections  in  the  circuit 
or  the  electrode,  this  change  being  within  the  working 
range  between  too  long  an  arc  and  too  short  an  arc,  there 
is  considerable  variation  allowable — we  would  say  }i 
inch  to  3/16  inch;  whereas  anything  over  3/16  inch 
begins  to  be  too  long  an  arc,  and  rapidly  tends  to  be- 
come %  or  ^  inch  long,  in  which  case  no  welding  can  be 
done,  the  metal  of  the  electrode  melting  so  much  more 


208 


SPOT  AND  ARC  WELDING 


rapidly  than  the  work  that  there  is  not  crater  enough  in 
the  work  to  receive  the  electrode  metal;  and,  unless  the 
crater  in  the  work  is  as  large  or  larger  than  the  deposited 
electrode  metal,  no  welding  can  result.  For  instance, 
steel  cannot  be  welded  by  pouring  molten  steel  on  it  at 
any  temperature  except  molten. 

The  conditions,  then,  for  good  welding  are:  First, 
control  of  the  arc  length ;  second,  constant  rate  of  heat ; 
third,  a  good  operator ;  because,  with  the  first  two  condi- 
tions ideally  realized,  we  are  still  at  the  mercy  of  the  man 
that  he  guide  the  arc  to  weave  the  desired  joint  together. 

In  limiting  the  voltage  across  the  arc  some  appa- 
ratus has  been  equipped  with  relays  which  cut  the  arc 
out,  or  cut  resistance  in,  or  give  other  notifications  that 
the  arc  is  too  long.  Other  efforts  to  limit  the  voltage  of 
the  arc  have  been  made  by  reducing  the  open-circuit 
voltage  or  guardian  voltage  until  only  a  certain  length 
arc  could  be  held.  It  is  interesting  to  note  here  that  an 
arc  cannot  be  held  with  a  supply  at  the  voltage  across 
it;  in  fact,  the  values  begin  to  be  twice  the  voltage  of  the 
arc  before  any  arc  at  all  can  be  held.  This  is  true  of 
alternating  current  or  direct  current.  The  minimum 
voltage  at  which  an  arc  can  be  held  is  around  31  or  32 
volts  and  this  is  obtained  with  bare  wire  and  with  no  flux 
or  coating.  While  the  gases  of  coated  wires  help  to  hold 
the  arc,  they  also  raise  the  necessary  voltage,  and  hence 
raise  or  hold  about  the  same  the  minimum  voltage  at 
which  an  arc  can  be  held.  With  just  as  low  an  open- 
circuit  voltage,  an  arc  can  be  held  on  alternating  current 
as  on  direct  current.  With  alternating  current  the 
guardian  voltage  is  supplied  partially  by  inductive 
kicks  or  transformer  characteristics,  and  the  normal 


THEORIES  OF  ELECTRIC  WELDING  209 


open-circuit  voltage  can  be  lessened.  On  direct  current 
a  reactance  gives  a  like  action,  but  in  much  less  degree, 
naturally  the  average  voltage  across  the  arc  showing  the 
effect  of  these  also,  but  the  open-circuit  voltage,  at  least 
the  quite  open-circuit  voltage,  does  not  show  it.  The 
only  method  so  far  discovered  of  limiting  the  length  of 
arc,  without  moving  parts  and  without  losing  the  neces- 
sary open-circuit  or  guardian  voltages  for  puncturing 
through  dirt,  oil,  slag,  and  giving  good  penetration, 
is  by  the  alternating-current  special  transformer  for 
arc  welding." 

No  satisfactory  technical  explanation  has  been  offered 
for  the  ability  of  the  arc  to  deposit  metal  from  below. 
That  is  the  phenomenon  of  overhead  welding.  The 
same  expert,  fully  cognizant  of  the  theories  put  for- 
ward, looks  upon  the  matter  in  this  common-sense  way: 
"  Overhead  welding  depends  neither  on  the  machine  nor 
electrode,  except  in  the  case  of  completely-covered  elec- 
trodes where  a  special  covering,  thinner  and  harder,  i.e., 
freezing  more  quickly,  is  resorted  to  in  order  to  keep  the 
metal  and  slag  from  dropping.  Overhead  welding  is 
not  a  function  of  polarity,  or  the  metal  being  carried  in 
one  direction  by  the  flow  of  current,  but  simply  a  case  of 
capillary  attraction  of  the  molten  parent  metal  for  the 
molten  electrode  metal,  and  the  electrode  must  be  moved 
ahead  at  a  steady  constant  rate,  so  that  but  the  equivalent 
of  one  drop  is  molten  at  a  time,  and  this  drop  draws  up 
into  the  parent  metal  instead  of  dropping.  For  instance, 
one  drop  of  water  will  cling  to  the  ceiling,  but  more  than 
that  will  fall,  leaving  one  drop  remaining.  A  very  close, 
but  not  too  close,  arc  must  be  held  for  overhead  welding, 

"  Communicated  to  the  Author  by  C.  J.  Holslag,  Septennber,  1919. 
14 


210 


SPOT  AND  ARC  WELDING 


and  the  voltage  is  then  reduced,  and  hence  the  current 
must  be  increased  to  give  the  requisite  amount  of  heat. 
On  the  alternating-current  machine  this  change  is  auto- 
matic and  inherent.  On  other  systems  the  current  can 
be  arbitrarily  increased.  On  alternating  current,  also, 
the  progress  must  be  faster,  as  more  electrode  is  melted 
with  given  conditions." 

The  Physical  Behavior  of  the  Welding  Arc.^^ — "The 
phenomena  of  the  electric  arc  furnish  an  interesting  field 
for  careful  study.  The  production  in  so  restricted  a  re- 
gion of  a  temperature  so  high  as  to  volatilize  any  known 
substance  is  truly  marvellous.  The  means  by  which  the 
temperature  is  automatically  held  and  regulated  is  still 
more  wonderful.  Before  the  days  of  electric  welding  the 
remarkable  temperature  effects  of  the  arc  furnished  the 
chief  interest.  The  art  of  electric  welding  raises  a  new 
question:  the  manner  of  transference  of  the  material 
through  the  arc.  On  this  point,  the  experiments  of 
the  joint  Research  Committee  of  the  National 
Research  Council  and  the  Electric- Welding  Committee 
of  the  Emergency  Fleet  Corporation  have  yielded 
considerable  information. 

"1.  Data  culled  by  a  sub-cormnittee  on  the  physics  of 
the  arc  from  the  experiments  of  the  Research  Committee, 
together  with  results  obtained  by  Professor  R.  G.  Hud- 
son,  of  Massachusetts  Institute  of  Technology,  and 
results  obtained  by  Professor  C.  F.  Hale,  of  Albany 
Teachers'  College,  have  shown  conclusively  that  the  mode 
of  transfer  of  material  through  the  arc  is  totally  different 
from  the  mode  of  transport  through  liquid  electrolytes. 

"  The  amount  of  material  transferred  through  the  arc 

Communicated  to  the  author  by  Prof,  Allison  W.  Slocum,  University  of 
Vermont,  November,  1919. 


THEORIES  OF  ELECTRIC  WELDING  211 


was  in  some  cases  three  times  as  great,  and  in  other  cases 
only  one-thousandth  part  as  much  as  would  be  trans- 
ported through  an  electrolyte  by  Faraday's  laws. 

"  '  Positive  and  negative  ions/  as  used  by  Faraday, 
have  no  meaning  in  the  phenomena  of  the  electric  arc. 

"  2.  In  the  electric  arc  there  is  a  potential  difference 
between  the  electrodes  which  may  be  measured  with  a 
voltmeter.  This  potential  difference  proves  the  exist- 
ence of  an  electrostatic  field  between  the  electrodes  and 
a  consequent  electrostatic  pull  upon  the  surface  of  the 
electrodes  tending  to  remove  the  molten  metal.  A  simple 
calculation  of  the  magnitude  of  this  force  shows  that  it 
cannot  be  relied  upon  to  transfer  the  metal  across  the 
arc  to  the  plate.  It  could  not  even  remove  the  metal 
from  the  electrode  against  the  force  of  surface  tension 
alone  unless  the  surface  be  so  near  the  boiling  point  that 
the  surface  tension  becomes  practically  neghgible.  By 
no  possibility  could  it  remove  the  metal  and  carry  it  up 
against  gravity  as  in  the  case  of  overhead  welding. 

"  Moreover,  when  the  temperature  of  the  surface  is 
close  to  the  boiling  point  of  the  metal,  the  electrostatic 
pull  would  draw  the  metal  from  the  surface  in  threads 
like  glass  wool.  This  is  the  probable  explanation  of  the 
sharp  point  left  on  the  electrodes  which  have  been  used 
for  welding  with  alternating  current. 

Professor  R.  G.  Hudson  has  proposed  a  theory  in 
which  he  avoids  reliance  on  the  inadequate  electric  force 
by  supposing  the  formation  of  a  gas  in  the  electrode 
beneath  the  surface  which  by  its  expansive  pressure  ex- 
plosively propels  the  molten  metal  across  the  arc  gap. 
This  theory  is  published  in  the  Electric  Welding  Journal 
for  November,  1919. 


212 


SPOT  AND  ARC  WELDING 


"3.  Though  the  electrostatic  field  of  the  electromo- 
tive force  between  the  terminals  of  the  arc  is  ineffective 
in  pulling  metal  from  the  electrode,  it  is,  indeed,  the  all- 
important  factor  in  the  heat-producing  effect  of  the  elec- 
tric ciu^rent.  Electricity  produces  heat  only  while 
moving  in  the  direction  of  an  electric  force.  This  is 
true  whether  electricity  behaves  like  an  incompressible 
fluid  in  its  flow  or  flows  like  a  stream  of  electrons 
or  thermions. 

The  fall  of  potential,  which  exists  between  the  ter- 
minals of  the  electrodes,  occurs  chiefly  at  the  surfaces  of 
the  electrodes.  This  '  electrode  fall '  is  the  most  impor- 
tant feature  of  the  behavior  of  the  arc.  For  it  is  here  that 
the  heat  is  chiefly  produced. 

"  This  electrode  fall  is  in  part  conditioned  by  the  elec- 
trostatic force  required  to  pull  the  electrons  or  thermions 
from  the  metal  of  the  electrodes.  At  very  high  tempera- 
tures thermions  are  spontaneously  emitted  in  copious 
streams.  This  phenomenon  is  well  known  in  the  behavior 
of  tungsten  filament  lamps.  At  such  high  temperatures 
the  electrode  fall  is  small,  a  matter  of  a  few  volts.  At 
lower  temperatures  the  electrode  fall  is  larger.  It  is  very 
important  to  note  that  the  electrode  fall  diminishes  with 
rising  temperature  and  that  in  the  neighborhood  of  the 
boiling  point  of  such  metals  as  iron  it  changes  very 
rapidly  with  relatively  slight  changes  of  temperature. 
It  is  this  behavior  of  the  electrode  fall  that  gives  to  the 
electric  arc  its  extremely  stable  avitomatic  regidation  of 
the  temperature  of  the  surfaces  of  the  electrodes  regard- 
less of  the  conditions  behind  the  surfaces. 

"  The  rate  of  heat  production  is  proportional  to  the 
product  of  the  current  strength  and  the  electrode  fall. 


THEORIES  OF  ELECTRIC  WELDING  213 


When  the  arc  is  playing  steadily  the  rate  of  heat  produc- 
tion equals  the  rate  of  heat  dissipation.  If  any  change 
occurs  which  tends  to  increase  the  rate  of  dissipation,  this 
change  instantly  tends  to  cool  the  surface.  The  ten- 
dency to  cool  the  surface  is  rapidly  checked  by  the  in- 
crease of  the  electrode  fall  and  the  consequent  increase 
of  heat  production  at  the  surface. 

''4.  When  an  electric  current  is  flowing  through  an 
arc  it  is  surrounded  by  so-called  lines  of  force  which  be- 
have in  some  respects  as  stretched  elastic  bands  exerting 
a  normal  pressure  inward  upon  the  surface  and  through- 
out the  interior  of  the  material  of  the  arc.  This  effect  is 
known  as  the  pinch  action  of  the  current  upon  itself.  A 
calculation  of  its  magnitude  in  the  case  of  a  welding  arc 
shows  that  its  pressure  is  comparable  to  that  of  the  sur- 
face tension  of  a  stream  of  water  flowing  slowly  in  a  long 
thread  from  a  faucet.  The  regulative  influence  of  the 
surface  tension  on  the  stream  of  water  is  small  but  ap- 
parent. The  regulative  effect  of  such  a  pressure  on  a 
stream  of  vapor  of  one- thousandth  part  of  the  density  of 
water  would  be  one  thousand  times  as  great. 

"  The  pinch  action  of  the  current  may  be  considered 
as  having  the  effect  of  a  kind  of  tube  of  considerable 
stability  through  which  the  material  of  the  arc  is  flowing. 

"  In  accordance  with  the  considerations  stated  above 
and  the  general  data  reported  to  the  Research  Com- 
mittee by  various  experimenters,  the  sub-committee  on 
the  physics  of  the  arc  suggested  a  vapor  theory  of  the 
electric  arc.  Strong  evidence  for  this  theory  is 
constantly  accumulating.^^ 

Hagenbach  and  Landbein  {Archives  des  Sciences,  Jan.-Feb.,  1919)  have 
shown  that  for  current  intensities,  not  too  small,  the  anodes  of  metallic  arcs 
(Ag.  Cu.  Fe.  Na.  W.)  are  heated  at  the  tip  to  the  temperature  of  ebullition. 


214 


SPOT  AND  ARC  WELDING 


"  According  to  the  vapor  theory  of  the  arc,  its  be- 
havior consists  in  a  process  of  boihng  of  the  surface  of 
the  electrode;  the  transfer  of  the  vapor  through  a  kind 
of  tube  furnished  by  the  pinch  action  of  the  current ;  and 
the  condensation  of  the  vapor  on  the  surface  of  the  plate. 
In  the  interior  of  the  pinch-action  tube  there  is  a  core  of 
pure  iron  vapor  which  flows  through  the  core  exactly  as 
steam  flows  through  the  pipes  from  the  boiler  to  the 
radiator  in  a  steam-heating  plant  after  the  air  has  been 
completely  expelled. 

"  In  the  case  of  the  boiler,  the  heat  is  supplied 
through  the  bottom  of  the  boiler  and  causes  the  boiling 
commotion  throughout  the  volume  of  water.  In  .the  case 
of  the  arc  the  heat  is  applied  to  the  boiling  surface  and 
the  boiling  commotion,  when  it  exists,  occurs  only  in  the 
regions  immediately  beneath  the  surface.  This  is  the 
phenomenon  of  the  spluttering  of  the  arc. 

"  The  boiling  of  the  surface  is  accompanied  with  the 
absorption  of  heat  as  latent  heat  of  the  vapor.  This  heat 
is  again  set  free  when  the  vapor  condenses  upon  the 
plate.  The  flow  of  vapor  across  the  arc  is  limited  by  the 
rate  at  which  the  conductivity  of  the  plate  can  take  away 
the  heat  liberated  by  condensation. 

"  The  temperatures  of  the  surfaces  of  electrode  and 
plate  are  automatically  regulated  to  approximately  the 
boiling  point  of  the  metal  by  the  peculiar  action  of  the 
electrode  fall.  The  electrode  fall  at  the  plate  is  regu- 
lated by  the  force  necessary  to  supply  the  positive  charges 
to  the  arc.  The  electrode  fall  at  the  electrode  is  regu- 
lated by  the  force  required  to  supply  the  negative 
charges  to  the  arc.  And  both  electrode  and  plate 
are  automatically  held  steadily  at  the  right  temperature 
for  the  purpose. 


THEORIES  OF  ELECTRIC  WELDING  215 


"  The  vapor  behavior  of  the  arc  suggests  the  follow- 
ing rule  for  welding:  Choose  the  largest  current  per- 
mitted by  hub  conductance  of  the  plate  and  choose  the 
smallest  electrode  that  will  carry  the  chosen  current. 

The  vapor  theory  is  suggested  as  a  tentative  theory. 
Whether  it  will  completely  stand  the  rough  and  tumble 
of  careful  experimenting  remains  to  be  seen.  In  any 
case,  it  serves  to  direct  the  attention  of  the  welder  to  the 
most  important  factor  of  successful  welding — the  heat 
distribution  and  the  temperature  gradients  in  the  neigh- 
borhood of  the  welds." 

Practical  Aspects. — In  reviewing  the  work  of  spe- 
cialists who  have  investigated  the  science  of  arc  welding, 
one  very  encouraging  opinion  stands  out  clearly,  that  up 
to  the  present  time  no  obstacles  have  been  observed  that 
would  deter  the  use  of  the  process  for  the  joining  of 
heavy  structural  members.  The  general  caution  always 
exercised  by  technical  men  centres  on  the  skill  of  the 
operator.  As  previously  shown,  this  responsibility  may 
be  relieved  by  the  future  development  of  automatic  arc 
welding.  Until  that  time  it  will  be  the  duty  of  those  in 
charge  of  important  electric-welding  progress  to  select 
and  train  J;he  best  men  as  arc  welders.  Practically,  the 
art  of  arc  welding  reduces  to  the  man  who  makes  the 
weld,  but  this  man  must  have  behind  him  the  work  and 
encouragement  which  comes  from  those  whose  advocacy 
of  the  process  is  guided  by  common  sense  and  sincerity. 

For  purely  practical  purposes  a  test  that  may  prove 
interesting  was  made  at  the  Pottstown  demonstration  to 
show  the  effect  of  the  combination  of  spot  and  metallic- 
arc  welding.  Fig.  43  shows  the  four  sample  pieces. 
No.  1  was  a  single  spot  weld  made  in  12  seconds  with  the 


216 


SPOT  AND  ARC  WELDING 


SINGLE  SPOT  Yz  PLATE 

12  SEC.  AMR  '31200   16750  LBS. 

ULTIMATE  TENSILE  LBS.  46500 


full  capacity  of  the  27-inch  portable  spot  welder.  No.  2 
was  a  lap-joint  arc  welded  with  direct  current  on  both 
lajjs  and  made  in  three  layers.  Nos.  3  and  4  were  similar, 
but  the  order  of  the  welding  was  reversed,  i.e..  No.  3 

sample  was  arc  welded 
first  and  then  spot 
welded,  and  No.  4  was 
first  spot  welded  and  then 
arc  welded.  The  results 
would  indicate  little  ad- 
vantage of  the  combina- 
tion, but  the  arc  weld 
parted  at  the  joint  under 
an  ultimate  tensile  which 
slightly  exceeded  the  ulti- 
mate tensile  in  the  com- 
bination joint  which  broke 
the  plate  material  and  left 
the  joint  intact.  The  ulti- 
mate tensile  for  each 
sample  follows: 


A/o.^ 


/ 


/ 


ARC  WELD -3  LAYERS -D.  C. 
ULTIMATE  TENSILE  LBS  106800 


ARC  WELD  ic  SPOT  WELD 
APPRO.  DIAM.  SPOT  '^'6  " 
ULTIMATE  TENSILE  LBS.  106500 


SPOT  WELD  &  ARC  WEED 
APPRO.  DIAM.  SPOT  I  fie  " 
ULTIMATE  TENSILE  LB5.J065OO 

Fig.  43. — Experiment  in  combination  of  arc  and 
spot  welding. 


No. 
No. 
No. 
No. 


1. 
2. 
3. 
4. 


.  46,500 
.  106,800 
.106,500 
.106,500 


Nos.  3  and  4  joints 
were  afterwards  pried 
open  with  a  wedge  in  or- 
der to  examine  and  measure  the  size  of  spot.  In  the 
former  this  was  estimated  to  be  13/16  of  an  inch,  and  in 
the  latter  1  5/16  of  an  inch  in  diameter. 


THEORIES  OF  ELECTRIC  WELDING  217 


Su7nmary. — The  differences  of  opinion  of  tech- 
nicians might  make  the  practitioner  experience  a  feeling 
of  doubt.  This  is  a  natural  stage  in  the  develop- 
ment of  any  art  or  practice,  and  must  be  so  considered  in 
discussing  and  applying  the  theories  advanced.  The  only 
condemnation  is  for  those  who  obstruct  advancement  for 
the  sake  of  gain,  or  who  enhance  some  trivial  character- 
istic of  the  process  to  the  detriment  of  a  better  under- 
standing of  the  whole.  The  work  of  theorists  is  mainly 
to  find  defects  in  order  to  cure  them  and,  with  the  instru- 
mentalities now  available,  it  is  certain  to  follow  that  the 
results  of  their  work  will  advance  the  practice  to  a  higher 
state  of  efficiency. 


APPENDIX 


APPENDIX  I 

The  Classification  Societies  Have  So  Far  Considered  and 
Approved  of  the  Application  of  Electric  Welding  to  the 
Following  Parts  of  Vessels: 

Deck-Rail  Stanchions  to  Plating 

Clips  for  Detachable-Rail  Stanchions 

Continuous-Railing  Rods  (Joints) 

Attaching  Deck  Collar  (L  Rings)  araund  Ventilators 

Attaching  Deck  Collar  (L  Rings)  around  Smokestack 

Attaching  Cape  Rings  around  Smokestack_,  Pipes^  etc. 

Attaching  Galley  Fixtures  to  Plating 

Attaching  Bath  and  other  Fixtures  in  Officers'  Quarters 

Attaching  Cowl-Supporting  Ringsi  to  Ventilators 

Bulwark  Rail  Top  Splicing  and  End  Fittings 

Skylights  over  Galley 

{a)  Engine-room  Stairs  and  Gratings 

(h)  Boiler-rt)om  Stairs  and  Gratings 

Attaching  (a)  and  (6)  to  Plating  Grab  Rods  on  Casing 
All  Stairs  and  Ladders^  including  Rail  Attachments 
Door  Frames  to  Casings  Hinges^  Catches^  Holds^  Coach-hooks^  etc. 
Clips  for  Attaching  Interior  Wood  Finish  to  Casing 
Entire  Screen  Bhd 

•% 

Also  Coal  Chutes 

Butts  of  W.T.  and  O'.T.  Boundary  Bars  on  Bulkheads  or  Floors  in 

Double  Bottom 
Ventilator  Cowls 
Stacks  and  Uptakes 

Bulkheads   (that  are  not  structural  parts  of  the  ship),  partition 
bulkheads  in  accommodation 
218 


APPENDIX  219 

Framing  and  Supports  for  Engine  and  Boiler-room  Flooring  or 

Gratings 
Cargo  Batten  Cleats 
Tanks  (that  are  not  structural  parts) 
Shaft  Alley  Escapes 

Steel  Skylights  over  Accommodation  Spaces 
Engine-room  Skylights 

Grab  Rods  on  exterior  and  interior  of  Deck  Houses 
Deck  Houses  not  covering  unprotected  openings  through  weather 
decks 

Reinforcing  and  protecting  angles  round  manholes 
Joints  of  W.T.  Angle  Collars  at  frames  in  way  of  W.T.  Flats 
Other  parts  of  a  vessel  in  which  electric  welding  is  proposed  must  be 
submitted  for  consideration. 

March  25th,  1918. 

For  Lloyd's  Register  of  Shippings  J.  French 
For  American  Bureau  of  Shippings  Geo.  G.  Sharp 


APPENDIX  II 


Electrode  Material  for  Metallic  Arc  Welding^ 
Welding  Circular  No,  1. 

Chicago^  August  I,  1919. 

To  All  Concerned: 

It  is  intended  to  standardize  our  materials  used  for  metallic  arc 
welding.  A  copy  of  our  specifications  for  welding  materials  is 
attached  herewith. 

You  will  note  that  there  are  now  five  different  electrodes  shown 
as  Rock  Island  Nos.  1^  2^  4  and  5.  Any  additional  electrodes 
which  it  may  become  necessary  to  purchase  and  use  in  the  future 
will  be  given  a  Rock  Island  number^  and  supplements  covering  same 
issued  to  all  concerned. 

It  is  desired  that  Mr.  Sedwick  see  that  each  lot  purchased  meets 
the  specification^  except  for  the  actual  flowing  and  weldability  of 
the  metal^  which  will  have  to  be  determined  by  an  expert  welding 
operator  who  shall  be  designated  by  Mr.  Wanamaker  or  Mr.  Penning- 
ton— preferably  an  operator  at  Silvis. 

When  the  material  is  O.K.'d^  it  can  then  be  placed  in  Silvis 
stock,  it  being  assumed  that  all  metallic-arc-welding  electrodes  will 
be  delivered  to  the  Silvis  Store  and  distributed  from  that  point. 

The  electrodes  should  come  in  boxes  plainly  marked,  showing  the 
Rock  Island  number  and  kind  of  material. 

The  Store  Department  should  prevent  any  confusion  or  mixing  of 
the  different  specifications  or  analysis  of  electrodes,  preferably  by 
having  their  racks  or  bins  divided  into  different  sections,  one  section 
for  each  electrode  number.  This  would  hold  true  not  only  for  the 
Silvis  Store,  but  all  stores  where  metallic-welding  electrodes 
are  handled. 

*  Courtesy  of  E.  Wanamaker,  E.  E.,  Chicago,  Rock  Island  &  Pacific 
Railway. 

220 


APPENDIX 


221 


These  electrodes^  at  least  for  the  present,  will  all  be  received 
"  bare,''  as  called  for  in  the  specification.  At  Silvis,  a  sufficient 
percentage  of  the  Rock  Island  No.  1  electrodes  will  be  coated  to 
meet  the  demand  from  the  different  points.  All  of  the  Nos.  2,  S,  4 
and  5  electrodes  will  be  coated. 

The  coating  specifications  will  be  furnished  by  circular  letter, 
detail  instructions  regarding  same  to  be  furnished  by  Mr.  Wana- 
maker  or  Mr.  Pennington. 

All  electrodes  which  are  coated  at  Silvis  shall  be  bound  into 
l6-lb.  bundles — each  bundle  to  be  tagged,  showing  the  Rock  Island 
number  and  kind  of  electrode  material. 

The  electrodes  may  be  coated  on  shop  order  and  returned  to 
stock,  care  being  used  to  see  that  the  different  numbers  do  not  be- 
come mixed  or  confused. 

Copies  of  all  circulars  to  date  affecting  the  handling  of  coated 
electrodes  are  attached  herewith. 

W.  J.  TOLLERTON. 
SPECIFICATIONS  FOR  ELECTRODES  FOR  METALLIC  ARC  WELDING. 

The  following  specifications  to  be  used  for  purchasing  electrode 
material  for  metallic  arc  welding: 

Rock  Island  No.  1 — Mild  Steel — electrodes,  to  be  used  for  all 
ordinary  purposes. 

Chemical  Composition: 

Carbon   Not  over  0.18 

Manganese    Not  over  0.55 

Phosphorus   Not  over  .05 

Sulphur   Not  over  .05 

Silicon   Not  over  .08 

To  be  furnished  in  3/32'' — 1/8"— 5/32''  and  3/l6"  sizes. 

Rock  Island  No.  2 — Medium-High-Carbon  Steel — electrodes,  to 
be  used  for  purposes  where  a  medium-high-carbon-steel  property  is 
desired — preferably  for  driving-wheel  flanges  or  rail  work. 


222 


APPENDIX 


Chemical  Composition: 

Carbon  —    0.65-0.75 

Manganese  —    0.60  -  0.90 

Phosphorus  —  Not  over  .05 

Sulphur  —  Not  over  .05 

Silicon  —  Not  over  .08 
To  be  furnished  in  5/32"  size. 

Rock  Island  No.  3> — Nickel  Steel — electrodes^  to  be  used  where 
strength  and  elasticity  is  desired  for  strength  members^  such  as 
frames^  shaftings  axles^  etc.^  or  any  case  where  metal  of  such  quality 
is  required 

Chemical  Composition: 


Nickel  —  Not  less  than  1.50  or  over  2.0 

Carbon  —  Not  less  than  0.20  or  over  0.50 

Manganese  —  Not  less  than  0.28  or  over  0.60 

Phosphorus  —  Not  to  exceed  .05 

Sulphur  —  Not  to  exceed  .05 

Silicon  —  Not  to  exceed  .08 


To  be  furnished  in  5/32''  size. 

Rock  Island  No.  4- — ^Manganese  Steel — electrodes^  to  be  used  for 
all  hard-wearing  surfaces^  especially  so  where  extreme  toughness  and 
medium  hardness  are  required^  for  instance — track  steels^  steam- 
shovel  dippers^  dipper  teeth^  frame  jaws^  and  any  part  of  a  machine 
structural  work^  pressure  vessel  work^  etc.^  such  as  would  require 
metal  in  the  weld  of  extreme  toughness. 

Chemical  Composition: 

Manganese  —    10.0  to  14.0 

Carbon  —   .     1.0  to  1.25 

Phosphorus  —  Not  to  exceed  .05 

Sulphur  —  Not  to  exceed  .05 

Silicon  —  Not  to  exceed  .08 
To  be  furnished  in  5/32''  size. 


APPENDIX 


223 


Rock  Island  No.  5 — Medium-Carbon  Steel — electrodes^  are  pri- 
marily of  value  for  axles^  forgings^  piston  rods,  etc.,  or  in  any  case 
where  sufficient  carbon  content  is  desired  to  limit  abrasive  wear. 

Chemical  Composition: 

Manganese    —    0.30  -  0.60 

Carbon  —    0.38  -  0.52 

Phosphorus    —   05 

Sulphur         —   .05 

Silicon  —   08 

To  be  furnished  in  5/32"  and  3/1 6"  sizes. 

Material : 

The  material  from  which  the  wire  is  manufactured  shall  be  made 
by  best-approved  process. 
Physical  Properties : 

Wire  to  be  of  uniform  homogeneous  structure,  free  from  segre- 
gation, oxides,  pipes,  seams,  etc. 
Test: 

The  commercial  weldability  of  the  No.  1  wire  electrodes  shall  be 
determined  by  means  of  tests  by  an  experienced  operator,  who  shall 
demonstrate  that  the  wire  flows  smoothly  and  evenly  through  the 
arc  without  any  detrimental  phenomena. 
Surface  Finish: 

To  be  absolutely  free  from  oil  and  grease,  and  to  have  a  dull,  flat 
finish,  free  from  polish  or  scale. 
Packing : 

All  wire  shall  be  straight  and  cut  to  14-inch  lengths  and  shipped 
preferably  in  boxes  or  kegs  not  exceeding  300  lbs.  net  weight.  If 
shipped  in  bundles,  wrapping  material  must  be  free  from  oil  or 
grease.  Each  box,  keg  or  bundle  must  be  plainly  marked,  showing 
the  C.  R.  I.  &  P.  number,  together  with  the  kind  of  material 
and  weight. 


APPENDIX  III^ 


Lesson  I 

THE  ARC-WELDING  MACHINE 

It  is  important  that  the  operator  become  familiar  with  the  welding 
machine  before  attempting  to  use  the  arc  for  welding  operations. 
Two  drawings  are  reproduced  showing  the  names  of  parts  of  the 
welder  set.  It  is  not  necessary  for  the  operator  to  memorize  the 
names  of  the  detail  parts  except  that  he  should  understand  the  loca- 
tion and  purpose  of  the  essential  parts  as  follows: — Brushy  Brush- 
holder^  Commutator^  Exciter  Commutator^  Field  Coils^  Motor^  Exciter^ 
Grease  Cup^  Ball  Bearingis^  Shafts  Bracket^  Frame^  Poles.  Any 
electrician  can  point  out  these  parts  on  the  welder  set  if  the  operator 
is  unable  to  do  so. 

The  arc-welding  generator  is  electrically  separate  from  the  motor 
which  drives  it.  A  welding  generator  may  be  driven  by  either  a  direct- 
current  motor  or  an  alternating-current  motor  or  by  a  steam  or  gaso- 
line engine.  The  source  of  power  to  drive  the  welding  generator  has 
nothing  whatever  to  do  with  the  behavior  of  the  welding  generator; 
provided  of  course^  it  is  furnished  in  sufficient  quantity  and  turns  the 
welding  generator  at  the  proper  speed.  The  motor  end  of  the  welding 
machine  is  like  any  other  motor  of  the  same  rating. 

The  principle  of  operation  of  the  welding  generator  is  very  simple 
to  the  man  who  has  had  some  experience  with  direct-current  gener- 
ators^ but  is  difficult  for  any  one  else  to  understand.  For  the  benefit 
of  the  man  who  has  had  electrical  experience,  it  is  sufficient  to  state 
that  the  welding  generator  is  merely  a  specially-designed  separately- 
excited  generator  with  a  differential  compound  winding  and  that  an 
inductive  ballast  is  used  in  the  arc  circuit.  It  is  desirable  for  the 
operator  to  understand  the  principle  of  operation  of  the  welding  set 

*  Courtesy  of  Lincoln  Electric  Co.,  Cleveland,  Ohio. 


APPENDIX 


225 


15 


226 


APPENDIX 


as  well  as  the  electrician  understands  it^  but  it  is  not  absolutely  neces- 
sary. The  accompanying  cut  shows  the  volt-ampere  characteristic 
and  the  wiring  diagram  of  the  welding  generator. 

The  welding  outfit  should  always  be  installed  by  an  electrician. 
All  cables  are  labelled  and  the  direction  of  rotation  is  marked  so  that 
no  difficulty  will  be  experienced  in  installing  the  outfit  without  the  use 
of  a  wiring  diagram. 

The  stabilizer  is  made  up  of  coils  of  wire  around  a 
laminated  steel  core  and  its  purpose  is  to  make  the 
arc  steady  and  easy  to  operate. 

An  electrician  should  explain  to  the  operator  the 
proper  method  of  starting  the  outfit. 

The  control  panel  contains  the  apparatus  with  which 
the  operator  controls  the  behavior  of  the  welding  gen- 
erator^ adjusting  it  to  give  the  proper  amount  of  heat 
for  welding.  Two  cuts  are  shown  showing  two  types  of 
control  panel  used.  The  portable  type  accomplishes 
the  same  thing  as  the  stationary  type.  The  voltmeter 
and  ammeter  are  left  off  the  portable  type  on  account 
of  the  fact  that  they  are  too  fragile  to  stand  the  rough 
use  to  which  they  would  be  subjected  on  portable 
equipment. 

Fig.  47  shows  the  ordinary  equipment  used  by  the 
operator^  and  welding  table.  Referring  to  Fig.  59, 
the  proper  clothing  for  an  operator  is  shown^ — it  con- 
sists of  black  cap^  unionalls^  cotton  gauntlet  gloves^ 
split-leather  apron. 


Fig.  45 —Station- 
ary panel. 


ADJUSTMENT  OF  MACHINE 

1 .  Open  main  switch  and  control  switch  on  panel. 

2.  Start  welding  set. 

3.  Turn  rheostat  as  far  as  it  will  go  to  the  left. 

4.  Close  control  switch  into  position  marked  100.  (In  this  posi- 
tion the  current  in  the  arc  will  be  approximately  100  amperes.) 

5.  Put  a  piece  of  5/32"  welding  wire  in  the  metal-electrode  holder. 


APPENDIX 


227 


6.  Place  a  piece  of  boiler-plate  scrap  on  welding  table  to  prac- 
tice on. 

7.  Close  main  switch  on  panel. 

8.  Sit  down  on  stool  in  front  of  welding  table.  Take  hand  shield 
in  left  hand^  metal-electrode  holder  in  right  hand.  With  shield  held 
in  front  of  face^  touch  boiler  plate  with  end  of  welding  wire.  The 


Fig.  46. — Portable  panel. 


result  will  be  a  spark  and  the  welding  wire  will  stick  to  the  boiler 
plate.    Let  go  of  electrode  holder  and  open  main  switch  on  panel. 

9.  With  a  new  piece  of  welding  wire^  and  face  shield  in  front  of 
face^  scratch  welding  wire  sidewise  on  boiler  plate  to  get  sparky  then 
draw  welding  wire  about  an  eighth  of  an  inch  away  from  the  plate. 
Hold  welding  wire  vertical  to  boiler  plate^  otherwise  arc  will  be  diffi- 
cult to  start. 

Repeat  the  above  operation  until  an  arc  can  be  maintained  as  long 
as  desirable.  The  beginner  should  burn  from  75  to  100  pieces  of 
welding  wire  at  this  practice^  observing  through  the  shield  what  hap- 
pens in  the  arc.    As  the  operator  becomes  more  skilful^  he  should  try 


228 


APPENDIX 


to  hold  a  shorter  arc.  The  proper  length  is  about  an  eighth  of  an 
inch.  The  operator  should  spend  about  15  hours  on  this  kind  of 
practice.  The  amount  of  current  or  amperes  required  for  welding 
depends  principally  upon  the  size  welding  wire  used.  Three- 
sixteenths-inch  welding  wire  requires  about  150  amperes.  (Turn 


Fig.  47. — Operator's  tools. 

rheostat  as  far  to  left  as  it  will  go  and  close  control  switch  into  150- 
ampere  position.)  For  points  in  between  100  and  150  amperes^  turn 
rheostat  to  right^  with  control  switch  in  150-ampere  position. 

Lesson  II 

STARTING  THE  ARC 

This  exercise  deals  with  the  proper  method  of  starting  and  stop- 
ping an  electric  arc.  The  beginner  usually  draws  an  arc  and  starts 
to  weld  at  whatever  point  the  arc  happens  to  start  operating  properly. 
In  other  words,  the  beginner  usually  welds  where  it  is  possible  for 
him  to  weld  rather  than  welding  in  a  predetermined  place.  The  pur- 
pose of  this  exercise  is  to  give  the  operator  sufficient  control  of  the 
arc  to  enable  him  to  weld  at  any  place  he  may  decide  upon. 

1 .  Place  a  piece  of  scrap  boiler  plate  on  the  welding  table.  With 
a  piece  of  soapstone  mark  a  line  across  the  plate.  Now  weld  a  bead 
as  nearly  as  possible  to  the  right  of  this  line.  Make  the  bead  as 
straight  as  possible.  Repeat  this  operation  until  a  perfectly  straight 
bead  1^"  from  the  predetermined  line  can  be  laid  down. 

2.  In  this  exercise  the  operator  should  print  his  initials  on  a  piece 


APPENDIX 


229 


of  scrap  boiler  plate  and  weld  a  bead  over  the  lines.  Having  produced 
a  perfect  set  of  initials  in  this  manner^  take  another  piece  of  scrap 
boiler  plate  and  make  the  initials  the  same  size  without  previously 
printing  them  with  soapstone.  The  operation  should  be  repeated 
until  the  operator  can  reproduce  his  initials  without  following  the 
lines.    The  purpose  of  this  exercise  is  to  train  the  operator  to  control 


Fig.  48.— Sample  of  Beads. 


an  arc  and  lead  it  in  a  predetermined  direction.  It  also  involves  the 
training  of  the  operator's  eyes  to  see  where  he  is  leading  the  arc. 
This  will  be  difficult  at  firsts  owing  to  the  fact  that  the  operator  can 
see  nothing  but  the  arc  itself  through  the  protective  glass. 

S.  The  operator  should  now  take  hammer  and  chisel  and  examine 
the  beginning  of  several  beads  which  he  has  made.  It  will  be  found 
that  the  beginning  of  the  bead  is  usually  not  securely  welded  to  the 
plate.    This  is  due  to  the  fact  that  the  arc  was  held  too  long  at  the 


230 


APPENDIX 


instant  the  bead  was  started.  The  operation  of  starting  the  are  at 
the  predetermined  point  should  be  repeated  with  this  fact  in  view 
until  a  satisfactory  weld  is  made  at  the  beginning  of  the  bead. 

4.  The  end  of  the  bead  is  quite  as  important  as  its  beginning.  In 
referring  to  beads  which  the  beginner  has  previously  made^  it  will  be 
found  that  a  considerable  crater  has  been  left  at  the  point  at  which 
the  arc  was  broken.  The  objection  to  this  crater  is  that  it  is  difficult 
to  start  welding  at  this  point  when  it  is  desirable  to  continue  the 
bead.  The  crater  may  be  filled  before  the  arc  is  finally  broken  by 
merely  crowding  down  the  arc  until  the  desired  amount  of  metal  is 
added^  and  breaking  the  arc  suddenly  by  pulling  the  wire  sharply  to 
one  side.  The  operator  should  practice  this  operation  until  he  is  able 
to  finish  a  bead^  leaving  a  crater  of  not  to  exceed  3/1 6  of  an  inch 
in  diameter. 

5.  The  exercises  outlined  in  the  preceding  four  paragraphs  should 
occupy  at  least  ten  hours  of  the  operator's  time.  The  following 
sample  is  to  be  made  as  to  the  record  of  the  operator's  ability  to  start 
and  stop  an  arc  properly: 

Material  required:  one  12"xl2"x%"  piece  of  boiler  plate;  three 
sizes  of  electrode  are  required —  8/1 6''^  5/32"^  1/8". 

No  marking  with  soapstone  is  to  be  done  on  the  plate.  Referring 
to  the  photograph  reproduced  herewith^  the  first  three  rows  of  beads 
arc  to  be  made  with  3 /1 6'^  wire^  using  approximately  150  amperes^ 
Each  bead  should  be  one  inch  long.  The  beads  should  be  three-quar- 
ters of  an  inch  apart.  They  should  be  straight  and  parallel.  Each 
bead  should  have  a  perfect  weld  at  its  start  and  a  very  small  crater  at 
the  finish.  The  next  five  beads  are  to  be  made  using  5/32"  electrode 
and  the  next  two^  using  electrode^  with  about  125  and  100  amperes^ 
respectively.  One  side  of  the  plate  should  be  completely  welded  in 
accordance  with  the  above  instructions.  The  plate  should  then  be 
turned  over  and  the  operation  repeated  and  perfected  on  the  other 
side  of  the  plate. 


APPENDIX  IV 


Lesson  III 

BUILDING-UP  OPERATION 

The  purpose  of  this  exercise  is  to  show  the  operator  the  proper 
method  of  building  up  several  layers  of  welded  material.  It  is  as- 
sumed that  in  Lesson  II  the  operator  has  learned  to  deposit  metal 
from  the  welding  wire  on  a  piece  of  boiler  plate  and  have  it  entirely 
welded  along  the  line  of  fusion.  Until  the  operations  outlined  in 
Lesson  II  are  completely  mastered,  it  is  useless  to  proceed  with  the 
exercise  of  building-up  operations. 

Material  required:  One  10"xl2''x^"  piece  of  boiler  plate.  One 


Fig.  49. — Built-up  pads  of  deposited  metal. 

size  of  electrode,  5/32  of  an  inch,  is  required.  The  current  should  be 
about  125  amperes. 

Referring  to  the  photograph  reproduced  herewith,  three  pads  are 
to  be  built  up  on  the  face  of  the  plate.  These  pads  are  to  be  6"  long, 
2"  wide,  l"  high.  The  first  pad  starting  from  the  left-hand  side  of 
the  plate  is  to  be  built  up  without  any  particular  design  or  pattern, 
and  without  brushing  or  cleaning  of  the  oxide-covered  surfaces. 

The  next  pad  is  to  be  built  up  following  the  definite  pattern.  First, 
brush  the  spot  on  which  the  second  pad  is  to  be  built  very  thoroughly 
with  a  wire  brush.    Second,  build  up  a  single  layer  of  metal  the  width 

231 


232 


APPENDIX 


of  the  pad^  usin,g\  a  series  of  beads  laid  along  the  6"  dimension^ 
always  starting  at  one  end  and  finishing  at  the  other  end.  Having 
deposited  the  first  layer^  the  oxide-covered  surfaces  must  be  brushed 
thoroughly  with  a  wire  brush.  Each  layer  should  be  brushed  at  least 
three  minutes.  The  second  layer  of  the  pad  should  be  built  up  so 
that  the  beads  run  at  right  angles  to  the  beads  of  the  first  layer^  i.e., 
the  beads  aire  parallel  to  the  2''  dimension  of  the  pad.  This  practice 
is  commonly  called  lacing.''  The  second  layer  to  be  as  thoroughly 
brushed  as  is  required  upon  finishing  the  first  layer.  Each  succeed- 
ing layer  should  be  thoroughly  brushed. 


Fig.  50. — Cross-section  of  pad. 


The  third  pad  is  to  be  built  up  in  exactly  the  same  manner  as  the 
second  pad,  with  the  exception  that  in  place  of  brushing  the  work 
with  the  wire  brush  only  between  each  layer,  the  oxide  must  be 
entirely  cleaned  off  by  the  use  of  the  hammer  and  chisel.  It  will 
be  noted  that  the  oxide  may  be  removed  by  comparatively  light 
blows  on  the  chisel.  It  is  not  necessary  to  cut  away  any  metal  to 
knock  the  oxide  from  the  top  of  thei  layer  with  a  chisel.  The  wire 
brush  may  be  used  to  brush  the  oxide  off  the  metal  after  it  has  been 
cut  away  with  a  chisel. 

The  operator  has  now  completed  three  pads.  The  first  pad  il- 
lustrates how  welding  should  not  be  done.  The  second  pad  illustrates 
a  fairly  satisfactory  practice.  The  third  pad  illustrates  the  best 
practice.    If  possible,  the  operator  should  have  this  sample  sawed 


APPENDIX 


233 


diagonally  through  the  three  pads.  It  should  then  be  set  up  on  a 
grinding  machine  and  a  fine  surface  ground  on  the  cut  section  of  the 
pads.  This  can  be  done  in  a  tool  room.  The  ground  surface  should 
then  be  painted  with  diluted  sulphuric  acid  or  tincture  of  iodine.  It 
will  then  be  easy  to  compare  the  quality  of  the  metal  in  the  three 
pads.  The  operator  should  also  observe  carefully  the  line  of  fusion 
between  the  pads  and  the  original  plate.  This  fusion  must  be  per- 
fect if  the  weld  is  of  any  value.  The  photograph  reproduced  here- 
with illustrates  the  appearance  of  a  good  line  of  fusion. 

Lesson  IV 

PLATE  WELDING 

This  exercise  is  one  of  the  most  important  of  the  series  because 
the  welding  of  plate  is  the  most  frequent  application  of  the  electric 
arc-welding  process.  The  welds  which  must  be  made  in  structures 
made  of  plate^  such  as  tanks^  are  not  always  horizontal^  so  that  the 
operator  must  learn  to  weld  not  only  in  the  horizontal  position  but 
also  in  the  vertical  and  overhead  positions.  Three  samples  are  to 
be  made  as  the  record  of  the  operator's  ability  to  weld  in  the  hori- 
zontal position  and  the  vertical  and  straight  overhead  positions. 

Material  required:  Six  10"xl2"xl4"  pieces  of  boiler  plate 
beveled  45  degrees  on  one  12"  edge^  5/82"  electrode  with  125  to 
150  amperes. 

1.  The  operator  should  spend  approximately  ten  hours  in  pre- 
liminary practice.  Several  pieces  of  scrap  boiler  plate  should  be 
beveled  and  tacked  together  as  shown  in  the  accompanying  photo- 
graph. These  plates  should  then  be  set  up  vertically  and  welded, 
starting  at  the  bottom  and  welding  up.  The  operator  should  use 
his  own  resourcefulness  in  arriving  at  the  best  way  to  make  a  weld 
in  this  position,  trying  several  different  methods  and  observing  the 
following  points:  Does  the  weld  extend  completely  from  the  inner 
to  the  outer  edges  of  the  plate  ?  Does  the  heating  of  the  plate  cause 
sufficient  expansion  and  contraction  to  affect  the  character  of  the 
weld?    Does  the  expansion  and  contraction  caused  by  the  heating  of 


234 


APPENDIX 


the  plate  produce  a  warping  or  buckling?  After  the  operator  has 
satisfied  himself  on  these  points^  two  pieces  of  scrap  boiler  plate 
should  be  beveled  and  placed  in  position^  ready  to  weld  straight 
overhead^  and  the  operator  should  try  to  weld  them  together  in  this 
position^  welding  from  the  under  side  only.  The  operator  should  put 
the  pieces  approximately  one-sixteenth  of  an  inch  apart  for  this 
exercise.    This  kind  of  welding  is  very  difficult  and  requires  a  con- 


FiG.  51. — Tacked  plates. 


siderable  amount  of  practice  to  master.  It  will  be  found  that  the 
operation  will  be  somewhat  easier  if  150  amperes  is  used  on  5/32" 
electrode  at  first.  In  welding  beveled  plates^  the  operator  should 
remember  that  the  welding  wire  or  electrode  should  be  held  as  nearly 
perpendicular  to  the  surface  being  welded  as  possible^  and  that  good 
welding  can  only  be  accomplished  when  a  short  arc  is  maintained. 
The  operator  should  pay  particular  attention  to  the  difference  in 
sound  between  a  long  arc  and  a  short  one.  A  long  arc  sputters 
and  has  a  distinct  hissing  sound.  It  is  impossible  to  weld  with  such 
an  arc.  A  short  arc  has  a  rapid-fire  metallic  click  which  may  be 
readily  distinguished.  The  operator  should  maintain  a  short  arc  on 
all  classes  of  welding.  Where  possible^  an  electrician  should  be  asked 


APPENDIX 


235 


to  connect  a  low-reading  voltmeter  across  the  arc^  so  that  the  voltage 
may  be  read  while  the  operator  is  welding.  The  voltmeter  siiould 
read  from  15  to  18  volts  while  the  arc  is  in  operation.  The  greatest 
amount  of  heat  is  obtained  on  tlie  work  when  the  electrode  holder  is 


Fig.  52. — Horizontal,  vertical  uud  overhead  samples. 

negative.  This  is  the  proper  connection  for  both  metal  and  carbon 
electrode  work. 

While  the  arc  is  in  operation^  there  will  be  a  circular  spot  of 
molten  metal  upon  the  work.  The  operator  should  concentrate  his 
attention  upon  the  side  of  this  molten  spot  of  metal  which  is  in  the 
direction  of  motion  of  the  electrode.  This  may  also  be  described 
as  the  forward  edge  of  the  circular  spot.  The  arc  should  be  directed 
on  this  pointy  since  it  is  at  this  point  that  the  greatest  amount  of 
heat  is  desirable.    It  is  possible  to  make  an  electric  weld  only  when 


236 


APPENDIX 


the  globule  of  molten  metal  from  the  welding  wire  is  thrown  into 
molten  metal  on  the  piece  being  welded.  If  the  globule  of  metal 
drops  on  metal  which  is  not  molten^  it  may  sticky  but  it  will  not  be 
welded.  The  operator  should  study  the  action  of  the  metal  in  the 
heat  of  the  arc  very  carefully.  The  operator  should  begin  to  realize 
at  this  point  that  merely  holding  an  arc  is  not  necessarily  welding 
but  that  the  art  of  welding  is  90  per  cent,  brain  work  and  10  per 
cent,  manual  labor. 

2.  Place  the  horizontal  sample  of  welding  in  position  on  the 
welding  table.  Put  a  5/32"  electrode  under  each  plate  in  a  position 
parallel  to  the  beveled  edges  and  about  from  the  lower  edge  of 
the  bevel.  This  will  raise  the  beveled  edges  higher  than  the  square 
edges  and  give  the  sample  a  ridge  through  the  centre.  The  object 
of  this  practice  is  to  allow  for  the  warping  of  the  plates  by  the 
heating  of  the  arc.  After  the  sample  is  welded  it  should  be  straight 
with  the  two  plates  squarely  in  line.  Place  the  edges  %  of  an  inch 
apart  all  the  way  across.  Tack  the  pieces  together  as  shown  in 
Fig.  51.  Now  with  140  amperes  and  a  5/32"  electrode^  weld  one 
layer  in  the  bottom  of  the  bevel  in  about  3"  sections.  By  this  is 
meant  that  the  operator  should  weld  3  inches^  skip  3  inches^  weld 
3  inches^  skip^  etc.^  until  he  has  gone  all  of  the  way  across  the 
plate^  then  go  across  the  plate  again^  filling  the  three-inch  gaps. 
This  is  to  minimize  the  effect  of  the  heating.  The  plate  will  then 
be  welded  with  one  layer  all  the  way  across.  The  operator  must 
manipulate  the  arc  in  such  a  manner  as  to  weld  the  lower  edges  of 
the  plate  completely  together^  i.e.,  the  metal  from  the  electrode  must 
run  clear  through  the  plates  and  be  firmly  welded  on  the  edges.  The 
operator  should  then  take  hammer  and  chisel  and  clean  the  oxide 
from  the  surface  of  the  welded  metal  very  thoroughly.  The  second 
layer  may  now  be  welded  into  the  bevel^  starting  at  one  end  and  finish- 
ing at  the  other  end.  This  layer  should  be  thin  and  should  not  extend 
higher  than  the  upper  surface  of  the  plates.  Chip  oxide  from  sur- 
face of  welded  material,  and  put  the  third  and  finishing  layer  on 
the  weld.  The  third  layer  should  extend  about  3/1 6  of  an  inch  beyond 
the  edge  of  the  bevel  on  each  plate,  and         above  the  upper  plate 


APPENDIX 


237 


surfaces.  The  plate  should  now  be  turned  over  and  a  reenforce- 
ment  of  equal  width  and  thickness  put  on  the  other  side.  The  pur- 
pose of  this  practice  is  to  make  the  section  of  the  weld  equal  on 
both  sides  of  a  centre  line  through  the  metal  of  the  plate.  If  the 
weld  were  reenforced  on  one  side  and  not  on  the  other  the  stress 
would  be  concentrated  on  the  side  which  was  not  reenforced  when 
the  weld  is  put  in  tension. 

3.  The  two  plates  should  be  tacked  together  as  in  first  exercise^ 
but  in  this  case  the  beveled  edges  are  to  be  set  vertical^  as  shovv^n 


in  Fig.  53.  The  weld  is  to  be  made  according  to  a  definite  pattern^ 
starting  at  the  bottom  and  finishing  at  the  top.  This  pattern  is 
triangular.  The  operator  should  start  on  the  right-hand  plate  at  a 
point  of  about  3/1 6  of  an  inch  to  the  right  of  the  beveled  edge^  hold- 
ing the  welding  wire  as  nearly  perpendicular  as  possible  to  the 
surface  being  welded.  The  movement  should  be  along  the  beveled 
edge  of  the  right-hand  plate  toward  the  farther  edge,  then  along 
the  beveled  edge  of  the  left-hand  plate  toward  the  nearer  edge^ 
extending  to  a  point  3/1 6  of  an  inch  to  the  left  of  the  bevel  on  the 
left-hand  plate^  then  across  to  the  starting  point.  Five-thirty-sec- 


FiG.  53. — Plates  welded  in  vertical  position. 


238 


APPENDIX 


ond  electrode  with  about  125  amperes  is  to  be  used.  The  operator 
must  pa}^  particular  attention  to  see  that  the  farther  edges  of  the 
plates  are  securely  welded  together.  A  considerable  amount  of 
metal  should  be  run  through  the  edges  to  make  this  certain. 

4.  For  the  sample  of  overhead  weldings  the  plates  may  be  tacked 
together  as  shown  previously^  except  that  the  opening  should  be 
approximately  of  an  anch.  The  two  plates  are  to  be  welded  in 
the  overhead  position  after  they  have  been  tacked.  Several  pieces 
of  plate  %  of  an  inch  thick^  '  wide  and  6"  long  are  to  be  cut^ 
and  a  3/32"  electrode  should  be  stutk  on  extreme  edge  of  one  of  the 
corners  so  that  the  electrode  stands  out  perpendicular  to  the  piece. 
The  purpose  of  the  electrode  is  to  serve  as  a  handle.  This  Vs"  piece 
is  to  be  pushed  through  quarter-inch  opening  between  the  plates 
from  the  under  side  and  to  be  brought  into  position  so  that  it  will 
form  a  backing  for  the  weld.  Fig.  52  shows  the  position  of  this 
plate.  After  the  plate  has  been  placed  in  position  it  may  be  tacked. 
The  use  of  this  plate  niakes  the  overhead  welding  somewhat  easier 
than  welding  without  its  use.  Start  the  overhead  weld  at  the  centre 
of  the  job  and  weld  toward  one  end.  A  definite  pattern  should  be 
followed.  Start  at  the  lower  edge  of  the  right-hand  plate  at  a 
point  3/1 6  of  an  inch  to  the  right  of  the  bevel.  Continue  along  the 
beveled  edge  of  the  right-hand  plate  up  to  the  backing  plate^  across 
the  backing  plate  and  down  the  beveled  edge  of  the  left-hand  plate 
to  a  point  3/1 6  of  an  inch  to  the  left  of  the  bevel.  This  will  form  the 
first  bead.  Now  start  the  second  bead  at  the  beveled  edge  of  the 
right-hand  plate  and  on  top  of  the  first  bead^  and  fill  in^  as  far  as 
possible^  the  opening  formed  by  the  beveled  edges  of  the  plates.  A 
third  bead  will  be  required  to  complete  this  operation.  The  operator 
now  has  two  surfaces  to  weld  on^  the  surface  formed  by  the  welding 
material^  which  should  be  approximately  vertical^  and  the  surfaces 
of  the  plates  to  be  welded.  The  pattern  of  the  first  pad  should  be 
followed  out  from  this  point  on  welding  at  the  junction  of  the 
previously-welded  material,  and  the  surfaces  of  the  plates  being 
welded  together  so  far  as  this  is  possible.  This  makes  the  weld 
more  a  vertical  weld  than  an  overhead  weld  and  considerably  sim- 


APPENDIX  239 

plifies  the  operation.  The  operator  should  use  about  150  amperes  to 
start  with^  cutting  it  down  to  125  or  less  as  the  plate  warms  up. 
Having  completed  one  end  of  the  weld  in  this  manner^  the  other  end 
may  be  welded  in  exactly  the  same  way.  It  will  be  found  that  the 
backing  plate  will  warp  and  tend  to  get  out  of  contact  with  the 
beveled  plates.  This  will  not  interfere  with  the  welding  and  will 
enable  the  operator  to  reenforce  the  weld  on  the  top  side,  which 
is  very  desirable. 

Lesson  V 

THIN-PLATE  WELDING 

This  exercise  is  to  give  the  operator  some  experience  on  thin- 
plate  welding.  The  difficulties  encountered  in  thin-plate  welding 
are  comparatively  simple  of  solution^  and  the  operator  is  left  to  use 
his  own  resources  to  a  considerable  extent  in  making  the  sample. 
The  great  difficulty  in  welding  thin  plate  arises  from  the  tendency 
of  the  arc  to  burn  through  the  thin  plate^  owing  to  the  great  inten- 
sity of  heat.  Practically  all  thin  plate  is  covered  with  a  heavy  scale 
of  blue  oxide,  and  it  is  necessary  to  get  this  oxide  cleaned  off  in 
order  to  make  a  good  weld.  This  may  be  done  with  hammer  and 
chisel  or  a  sand-blast.  The  operator  has  already  found  that  it  is 
necessary  to  have  clean  metal  in  order  to  make  a  good  weld.  The 
quickest  and  best  way  of  getting  clean  metal  is  to  sand-blast  the 
surfaces  to  be  welded.  This  applies  to  metal  of  all  thicknesses. 
The  reason  blue  oxide  gives  the  operator  trouble  is  that  it  is  a  very 
poor  conductor  of  electricity,  and  it  is  hard  to  get  the  arc  started 
on  an  oxide-covered  surface  and  also  that  the  oxide  gets  into  the 
metal  of  the  weld. 

Material  required :  One  piece  of  24"  x  30"  sheet  steel  approxi- 
mately 1/1 6  of  an  inch  in  thickness;  electrode  with  90  to 
100  amperes. 

1.  The  operator  should  study  the  drawing  reproduced  (See  Fig. 
56)  and  lay  out  the  pieces  to  be  cut  in  order  to  make  the  sand- 
blast pot  shown.    This  will  leave  some  scrap  material  around  the 


240 


APPENDIX 


edges  which  should  be  cut  with  a  hack-saw  into  pieces  approximately 
2"  X  4''.  The  operator  should  practice  welding  these  scrap  pieces 
by  laying  them  down  on  the  welding  table  and  welding  a  straight 
seam.  One  sample  should  also  be  welded  with  the  two  pieces  per- 
pendicular to  each  other  as  shown  in  accom- 
panying cut.  (Fig.  54.)  Approximately  two 
hours  should  be  spent  on  this  practice. 

2.  The  operator  should  now  cut  the  plates 
necessary  to  form  the  sand-blast  pot  and  weld 
them  together.  It  is  suggested  that  the  heads 
be  made  smaller  than  the  shell  so  that  they  fit 
on  the  inside.  They  should  set  back  from  the 
edge  of  the  shell  about  One  small  hole 

should  be  burned  through  at  the  location  of 
one  of  the  fittings  in  order  to  allow  the  heated 


J 


Fig.  54. — Two  pieces  welded 
one  perpendicular. 


air  to  escape  while  the  welding  is  being  done.  The  fitting  can  be 
put  on  the  sand-blast  pot  at  some  later  time  by  the  operator. 

Lesson  VI 


PRESSURE  WELDING 


This  exercise  is  in  the  nature  of  a  test  of  the  ability  of  the 
operator  to  make  a  solid  homogeneous  weld  which  is  properly  and 
thoroughly  done.  A  great  many  electric  welds  are  subjected  to 
steam  or  water  pressure  and^  unless  they  are  properly  made^  they 
will  show  leaks^  and  will  fail  at  a  point  below  the  pressure  for  which 
they  were  designed.  It  is  very  important  that  the  operator  should 
know  when  he  is  making  a  good  weld.  If  he  does  not  know  this^  his 
work  is  entirely  worthless.  He  is  as  poor  a  workman  as  the  jeweler 
who  must  smash  an  expensive  watch  in  order  to  find  out  how  it  was 
made.  A  skilful  operator^  who  has  a  reasonable  degree  of  judg- 
ment and  intelligence^  knows  when  he  is  making  a  good  weld.  If 
he  lias  made  a  section  of  a  weld  which  is  not  good^  he  should  either 
cut  that  section  out  and  reweld  it  or  inform  the  man  responsible 


APPENDIX 


241 


for  the  job  of  the  fact  that  a  particular  section  is  faulty.  A  man 
who  will  lie  to  himself  in  regard  to  the  quality  of  his  work  will 
lie  to  the  man  who  is  responsible  for  its  quality^  and  is  worse  than 
worthless  as  a  skilled  operator. 

Material  required:  One  18"  section  of  8''  wrougJit-iron  pipe 
or  seamless  tubings  two  %''-thick  boiler-plate  heads  to  fit  on  tlie 
inside  of  the  pipe  or  tube.  These  heads  should  be  beveled  45 
degrees  on  the  circumference^  6  pieces  of  V  black  wrought-iron 
pipe  6"  long^  one  piece  of  or  l"  pipe  according  to  the  size 


Fig.  55. — Boiler  flue  welding. 


water  pipe  used  in  the  shop  where  the  welding  is  done.  This  pipe 
is  to  be  connected  to  the  water  system  so  that  the  completed  sample 
may  be  tested  under  pressure.  Six  holes  are  to  be  drilled  at  inter- 
vals of  2'^  into  the. 8"  pipe  to  take  the  six  l"  pipes.  One  hole  is  to 
be  cut  to  take  the         or  l"  pipe. 

1.  The  heads  are  to  be  welded  into  the  pipe  as  shown  in  the 
accompanying  cut.  (Fig.  55.)'  The  operator  must  be  careful  to 
hold  a  short  arc  and  so  far  as  possible  keep  the  electrode  perpen- 
dicular to  the  surface  being  welded.  The  surfaces  which  are  to 
be  welded  must  be  clean  and  the  oxide  must  be  removed  from  each 
layer  of  metal  before  the  next  layer  is  welded^  by  the  use  of  sand- 
blast or  hammer  and  chisel.  The  l"  pipes  are  spaced  close  enough. 
16 


242 


APPENDIX 


Fig.  56. 


APPENDIX 


243 


together  so  that  some  difficulty  will  be  experienced  in  making  a  good 
weld  between  pipes.  This  is  done  purposely  because  it  is  a  diffi- 
culty frequently  encountered  in  practice.  The  operator  should 
mark  with  chalk  the  spots  where  he  believes^  owing  to  the  manner  in 
which  he  welded  the  sample^  that  the  leaks  will  occur.  Weld  the 
ends  of  the  six  l"  pipes  shut. 

2.  The  operator  should  connect  the  sample  to  the  water  system 
of  the  shop  and  test  it  for  leakage.  (It  is  advisable  to  pour  the  sample 
full  of  water  before  the  connection  is  made^  so  that  it  will  be  entirely 
filled  with  water  when  under  pressure.)  If  leaks  are  found^  the 
operator  should  cut  out  that  part  of  the  weld^  examine  the  weld 
and  find^  if  possible,  the  cause  of  the  leak.  The  defective  spots 
should  be  rewelded  and  the  test  repeated. 

Lesson  VII 

MISCELLANEOUS  JOBS 

The  object  of  this  exercise  is  to  give  the  operator  an  idea  of 
a  few  of  the  many  different  kinds  of  applications  of  the  process. 
A  great  deal  depends  upon  the  operator's  natural  resourcefulness 
in  planning  a  job.  One  of  the  difficulties  is  in  knowing  how  to 
go  about  a  job  so  that  it  may  be  done  with  the  least  possible,  exer- 
tion. The  more  highly  skilled  the  operator  is,  the  easier  will  be 
the  way  which  he  chooses  to  perform  the  operation.  This  involves 
careful  planning  of  the  operation  before  it  is  started.  The  operator 
who  cannot  plan  in  advance  exactly  how  he  is  going  to  do  the  job 
will  have  little  success  in  doing  it.  As  has  been  stated  before, 
success  in  welding  depends  more  upon  the  use  of  the  brain  than 
upon  the  use  of  the  hands.  The  operator  should  be  able  to  tell 
exactly  how  he  proposes  to  do  a  certain  job,  and  explain  the  reasons 
w^hy  he  intends  to  do  the  job  in  that  particular  way. 

Material  required:  One  riveted  section  as  shown  in  Fig.  57 ,  one 
angle-iron  section  as  shown  in  Fig.  58.  These  two  samples  need  not 
conform  to  any  specified  dimensions. 


APPENDIX 


1.  For  preliminary  practice^  the  operator  should  take  two  pieces 
of  ^/4"  scrap  boiler  plate^  and  tack  them  together  in  the  form  of  a 
lap  joint.  This  sample  should  then  be  set  up  in  the  vertical  position 
and  a  fillet  welded  on  the  under  side  of  the  lap^  similar  to  Fig.  57. 
Tliis  o})eration  should  be  repeated  until  the  operator  is  able  to  get 


Fig.  57. — Riveted  section. 

a  good  weld  and  the  fillet  has  a  uniform  appearance.  The  operator 
should  calculate  the  number  of  feet  per  hour  of  this  work  he  can 
do.  This  work  is  similar  to  the  operation  encountered  in  the  weld- 
ing of  a  caulking  edge  on  the  riveted  seam  of  a  steam  boiler.  It  is 
necessary  to  weld  only  one  bead  to  form  the  fillet;  140  to  150  amperes 
should  be  used.     The  operator  should  cut  across  the  seam  and 


APPENDIX 


245 


examine  the  fillet  to  determine  whether  or  not  he  has  made  a 
good  weld. 

2.  With  a  piece  of  scrap  boiler  plate  set  in  the  vertical  position^ 
the  operator  should  weld  a  number  of  circular  beads  approximately 

in  diameter.  After  eight  or  ten  of  these  circular  beads  have 
been  welded^  the  operator  should  clean  the  oxide  from  the  surfaces^ 
and  weld  a  second  bead  around  the  first  bead.  This  is  an  operation 
similar  to  that  of  welding  around  the  head  of  a  rivet.  One  of 
these  circles  should  be  cut  and  the  weld  examined  to  see  that  it 
has  been  properly  done  and  that  the  second  bead  is  fused  thoroughly 
to  the  plate  and  to  the  first  bead. 
This  is  an  operation  which  must  be 
thoroughly  mastered  before  pro- 
ceeding further. 

3.  This  exercise  consists  of  weld- 
ing two  pieces  of  heavy  plate  to- 
gether without  bevelling.  If  possible, 
two  pieces  of  %"-thick  boiler  plate 
should  be  obtained  for  the  exercise. 
Each  edge  which  is  to  be  welded 

should  be  set  in  a  horizontal  position    [   ; j 

and  a  bead  welded  along  the  centre  58.-Angle  iron  section. 

of  the  plate.  The  second  bead  should  then  be  welded  in  top  of  the 
first^  removing  the  oxide  from  the  first  before  the  second  is  applied. 
When  both  edges  are  thus  prepared  and  put  together^  the  operator 
will  have  what  amount  to  bevelled  edges  to  weld  together^  but  it  will 
be  necessary  to  weld  from  both  sides  in  order  to  complete  the  job. 
One  weld  of  this  nature  should  be  made  and  cut  so  that  the  operator 
may  examine  it  to  see  that  fusion  has  taken  place  throughout  the 
entire  weld. 

4.  This  exercise  is  the  one  shown  in  the  cut  (Fig.  57)  and  con- 
sists of  welding  the  caulking  edge  of  a  riveted  joint  and  welding 
around  the  rivet  head.  The  method  of  welding  the  caulking  edge 
has  been  previously  explained.  In  Welding  around  the  rivet  head 
R  is  advisable  to  heat  the  rivet  before  welding  around  the  head. 


246 


APPENDIX 


With  the  plate  in  a  vertical  position  (rivets  above  the  caulking  edge)^ 
draw  an  arc  on  the  head  of  the  first  rivet^  allowing  the  metal  from 
the  electrode  to  fall  clear  of  the  rivet  head.  This  should  be  con- 
tinued for  about  two  minutes  or  until  the  rivet  is  thoroughly  heated^ 
then  the  fillet  should  be  welded  around  the  rivet.  The  operator 
should  then  skip  two  rivets  and  repeat  the  operation  on  the  fourth 
rivet.  The  idea  of  skipping  rivets  is  to  keep  the  heat  distributed  so 
that  contraction  in  the  metal  will  not  set  up  shearing  stresses  in  the 
rivets.  By  following  the  above  practice^  a  very  tight  joint  will 
result  when  the  metal  of  the  rivets  and  plates  cools.  The  result  is 
similar  to  the  result  obtained  by  putting  in  a  hot  rivet  and  peening 
it  over.  When  such  a  rivet  cools^  it  contracts  and  pulls  the  plates 
tightly  together.  The  operator  may  turn  the  sample  over  and  repeat 
the  operation  on  the  other  side^  perfecting  it^  if  possible. 

5.  The  exercise  of  welding  an  angle-iron  section  is  one  which 
illustrates  a  type  of  job  which  is  quite  common.  The  angle  may 
be  cut  from  a  straight  angle  section  and  the  triangular  shape  cut 
out  with  a  hack  saw.  The  triangle  is  cut  out  so  that  the  angle  may 
be  bent  at  right  angles.  The  tip  of  the  triangular^  however,  must 
be  cut  square  off  in  order  to  allow  a  right  angle  to  be  bent  without  the 
edges  coming  entirely  together.  The  distance  between  the  edges 
after  the  angle  has  been  bent  through  90  degrees  should  be  equal 
to  the  thickness  of  the  angle.  The  operator  may  then  bridge  cross 
the  two  edges  from  one  side  allowing  as  little  metal  to  drop  down 
between  the  edges  as  possible.  Then  the  angle  should  be  turned 
over  and  the  space  between  the  edges  completely  filled  by  weld- 
ing in  one  or  more  layers. 

Lesson  VIII 

FLUE  WELDING 

This  exercise  deals  with  the  welding  of  flues  into  the  flue  sheet 
of  a  boiler.  This  work  is  encountered  in  fire-tube  boilers  of  all 
kinds.  The  operation  requires  a  considerable  amount  of  skill  in 
handling  the  arc.  A  preparation  of  the  flue  sheet  for  welding  in 
actual  practice  is  usually  what  makes  the  job  a  success  or  failure. 


APPENDIX 


247 


In  practice^  the  proper  way  of  preparing  a  flue  sheet  for  welding 
is  to  put  the  flues  in  exactly  as  if  they  were  not  to  be  welded.  The 
boiler  should  then  be  fired  at  least  once  to  allow  the  tubes  to  take 
their  permanent  set.  The  flue  sheet  should  then  be  sand-blasted 
to  clean  the  surfaces  to  be  welded.  If  no  sand-blast  is  available, 
the  pneumatic  tool  should  be  used  to  knock  the  oxide  off*  the  sur- 
faces, after  which  the  surfaces  should  be  thoroughly  brushed  with 
a  wire  brush,  then  the  welding  may  be  done.    If  the  work  is  pre- 


FiG.  59. — Welding  boiler  flues;  showing  arc  welder's  clothing  outfit. 

pared  in  this  manner  and  properly  welded,  the  results  will  be 
uniformly  successful. 

Material  required:    Section  of  boiler  plate  with  four  2" 

flues  rolled  in  as  shown  in  cut;  %"  electrode  with  100  amperes 
should  be  used. 

1.  Set  the  sample  as  shown  in  the  photograph.  Use  head  shield 
and  hold  the  electrode  holder  in  both  hands  as  shown  in  the  cut. 
The  first  flue  at  the  top  should  be  welded  starting  at  the  point  shown 
in  the  cut  and  welding  one-half  way  around,  moving  from  right 
to  left.  Then  the  other  one-half  welded  starting  at  the  original 
point  and  moving  downward  to  the  left.  The  second  flue  should 
then  be  welded  starting  at  the  bottom  and  welding  in  two  halves  so 
that  they  meet  at  the  top.    The  operator  may  then  weld  the  other  two 


248 


APPENDIX 


Hues  by  either  of  the  two  methods  illustrated^  depending  upon  which 
the  operator  likes  the  better.  One  of  the  flues  should  then  be  sawed 
in  half  to  show  the  quality  of  the  workmanship. 

Lesson  IX 

WELDING  STEEL  CASTINGS  WITH  CARBON  ARC 

This  exercise  illustrates  the  kind  of  work  done  in  a  steel  foundry 
and  in  certain  railway  shops.  The  carbon  arc  is  used  in  the  same 
manner  as  the  flame  of  an  oxy-acetylene  torch.  From  300  to  600 
amperes  are  required  for  carbon-electrode  work  of  this  nature.  The 
operator  must  use  both  hands  and  therefore  the  head  shield  is 
required.  The  carbon-electrode  holder  is  held  in  the  right  hand 
and  the  welding  rod  is  held  in  the  left  hand.  Carbon-electrode  weld- 
ing is  usually  considered  easier  than  metal-electrode  weldings  but 
there  is  considerable  skill  required  to  handle  a  carbon  arc  successfully. 

Material  required:  One  small  steel  casting  (Fig.  60),  carbon- 
electrode  holder^  carbon  electrode  in  diameter^  sharpened  to  a 
point  at  one  end,  300-ampere  welding  capacity  (if  300-ampere 
unit  is  not  available,  two  150-ampere  units  may  be  connected  in 
parallel),  3/1 6"  welding  rod. 

1.  For  preliminary  practice,  the  operator  should  use  the  300- 
ampere  carbon  arc  and  cut  into  small  pieces  several  pieces  of  boiler- 
plate scrap.  For  this  work  the  arc  should  be  held  approximately 
a  quarter  of  an  inch  long.  After  the  operator  has  practiced  suffi- 
ciently at  this  work  to  be  able  to  make  a  clean  cut  along  a  pre- 
determined line,  he  should  try  welding  together  two  pieces  of  boiler- 
plate scrap  using  the  carbon  arc  and  the  3/1 6"  welding  rod  to  fill  in 
with.  It  will  be  rather  difficult  to  control  the  arc  and  lead  it  in 
any  desired  direction. 

2.  If  3/1 6"  carbon  electrodes  are  available,  one  should  be  sharp- 
ened and  placed  in  the  metal  electrode  holder  and  some  cutting  of 
l/l6"  plate  done  using  150  amperes.  The  operator  should  be  able  to 
cut  a  straight,  clean  cut  upon  completing  this  exercise. 

3.  Using  the  riveted  sample  which  was  used  in  Lesson  VII,  the 


APPENDIX 


249 


operator  should  use  the  300-ampere  carbon  arc  to  cut  out  a  section 
of  the  upper  plate  between  two  rivets.  To  perform  this  operation^ 
the  plate  should  be  set  up  in  the  same  position  in  which  it  was 
welded  so  that  when  the  metal  is  melted  by  the  carbon  arc  it  can 
run  down  out  of  the  cut.  The  sample  should  then  later  be  welded 
flush,  using  the  metal-electrode  process.     After  working  with  the 


Fig.  60. — Small  steel  casting. 


carbon  arc  and  before  working  with  the  metallic  arc  on  this  job, 
it  will  be  necessary  to  chip  the  oxide  off  the  surface  to  be  welded, 
since  the  carbon  arc  forms  a  very  thick  coating  of  oxide. 

4.  This  exercise  deals  with  the  correction  of  a  flaw  in  the  steel 
casting  due  to  a  sand  spot.  This  defect  in  the  steel  casting  is 
caused  by  the  crumbling  of  the  mould.  It  is  necessary  to  burn  the 
sand  spot  out  with  the  carbon  arc  and  fill  in  new  material  from  the 
welding  rod.  If  there  is  no  sand  spot  on  the  casting  available,  it 
will  be  sufficient  for  the  operator  to  heat  a  spot  approximately 


250 


APPENDIX 


in  diameter  to  the  molten  state^  then  quickly  break  the  arc  and 
strike  the  molten  metal  a  sharp  blow  with  a  ball-peen  hammer.  If 
the  operator  had  performed  this  operation  on  a  sand  spot^  he  would 
have  floated  out^  most  of  the  sand  by  the  heat  of  the  arc.  The  sharp 
blow  with  the  hammer  throws  the  molten  sand  and  slag  out  of  the 
weld.  The  next  operation  is  to  fill  in  the  defect  with  new  material 
from  the  welding  rod.  The  operation  must  be  performed  as  rapidly 
as  possible^  otherwise  the  metal  added  as  well  as  the  metal  of  the 
casting  in  the  vicinity  of  the  weld  will  be  ruined  by  the  extreme 
heat.  The  arc  should  be  used  to  cut  off  short  pieces  of  the  weld- 
ing rod  and  then  these  pieces  should  be  melted  and  puddled  in  the 
proper  place.  In  case  the  arc  breaks  during  the  operation^  it  should 
be  started  again  on  solid  metal  that  is  not  molten  and  the  arc 
brought  over  into  the  welding  area  quickly.  If  the  arc  is  started  by 
touching  the  molten  metal  with  the  carbon  electrode^  it  is  very  likely 
that  the  weld  will  be  hard^  owing  to  the  fact  that  carbon  from  the 
electrode  has  gotten  into  the  weld.  As  soon  as  the  added  material 
has  been  fused  into  the  weld^  the  arc  must  be  broken.  There  is  always 
a  tendency  on  the  part  of  a  beginner  to  play  the  arc  too  long  on  the 
completed  weld  in  an  attempt  to  give  the  weld  a  smooth-finished 
appearance;  this  results  in  burning  of  the  metal.  In  steel-casting 
work  to  avoid  hard  spots  two  points  must  be  observed:  (1)  Some  pre- 
heating must  be  done  around  the  point  at  which  the  weld  is  to  be 
made  with  the  arc  so  that  it  will  not  be  cooled  too  suddenly.  (2) 
The  carbon  electrode  must  not  be  brought  in  contact  with  the  molten 
metal  as  explained  before. 

This  operation  should  be  performed  several  times  by  the  operator 
until  he  can  produce  a  weld  which  is  satisfactory  to  him. 

Lesson  X  ' 

CAST-IRON  WELDING 

The  purpose  of  this  exercise  is  to  give  the  operator  an  idea  of 
what  can  be  accomplished  with  the  electric  arc  on  cast  iron.  The 
operator  will  frequently  hear  amazing  statements  as  to  what  some 


APPENDIX 


251 


particular  operator  has  done  along  the  line  of  welding  cast  iron^ 
but  it  is  a  fact  that  there  are  only  a  few  commercial  applications 
of  the  process  in  the  welding  of  cast  iron.  The  difficulty  in  welding 
cast  iron  with  the  electric  arc  is  not  due  to  the  fact  that  the  metal 
cannot  be  properly  fused,  but  is  due  to  the  fact  that  the  sudden  intense 
heat  of  the  arc  over  a  local  area  results  in  the  production  of  a  hard 
weld  and  the  introduction  of  contraction  stresses  which  often  result 


Fig.  61. — Small  piece  of  cast  iron. 


in  cracking.  Using  the  carbon  welding  process,  cast-iron  welding 
rods  may  be  fused  into  a  cast-iron  piece.  Using  the  metal-electrode 
process  and  a  soft  iron  or  steel  electrode,  it  is  impossible  to  make 
a  reliable  weld  between  the  added  material  and  the  cast  iron.  Using 
the  metal-electrode  process,  certain  work  can  be  done  by  the  intro- 
duction of  steel  studs  in  the  cast-iron  pieces  to  be  welded  together, 
so  that  a  certain  amount  of  strength  is  obtained  by  the  bond  formed 
between  the  steel  studs  by  the  welded  material. 


252 


APPENDIX 


Material  required:  300-ampere  welding  capacity^  3/1 6"  cast-iron 
welding  rod.    One  small  grey-iron  casting  (Fig.  6l). 

A  small  grey-iron  casting  should  be  broken  and  the  edges  bevelled^ 
using  the  carbon  arc  for  cutting.  The  pieces  should  then  be  placed 
in  a  carbon  mould  so  that  the  molten  iron^  when  it  is  added^  will  not 
run  away  from  the  joint.  This  is  illustrated  in  Fig.  6l.  The 
carbon  arc  should  be  used  to  pre-heat  the  casting.  It  is  not  necessary 
to  heat  the  piece  to  a  red  heat.  The  carbon  arc  and  cast-iron  welding 
rod  should  then  be  used  to  fuse  the  added  material  to  the  piece. 
As  in  Lesson  IX^  care  should  be  exercised  not  to  play  the  arc  upon 
the  weld  any  longer  than  is  necessary  to  give  complete  fusion.  In 
case  the  metal  gets  too  hot  and  runs  badly^  the  arc  must  be  broken^ 
and  an  interval  of  time  allowed  for  it  to  cool  slightly  to  eliminate 
the  trouble.  After  the  weld  is  completed^  the  piece  should  be  wrapped 
up  securely  in  asbestos  paper  and  allowed  to  cool  slowly  for  6  or  8 
hours  (larger  pieces  require  from  18  to  24  hours  to  cool).  As  an 
alternative  to  wrapping  in  asbestos  paper^  the  piece  may  be  covered 
in  previously-heated  slacked  lime.  The  idea  of  the  lime  is  the 
same  as  the  asbestos^  to  cool  the  casting  slowly.  If  the  work  is 
properly  pre-heated  and  welded  rapidly  and  very  slowly  cooled, 
the  material  in  the  weld  will  be  as  readily  machinable  as  the  balance 
of  the  piece.  No  flux  of  any  kind  is  required^  although  borax 
may  be  used. 


APPENDIX  V 


This  design  was  prepared  by  me  ^  in  London  with  the  coopera- 
tion of  Mr.  W.  S.  Abell^  chief  ship  surveyor  of  Lloyd's  Register.  The 
design  is  such  that  a  lot  of  work  could  be  done  at  constructional 
works^  or  could  all  be  equally  readily  done  in  the  shipyard.  The 
work  is  closed  up  by  the  use  of  service  bolts. 

The  system  of  welding  in  view  is  the  arc^''  although  spot " 
welding  could  be  adopted  for  the  ground  work.  In  general^  the 
position  of  materials  does  not  differ  from  that  of  a  riveted  ship. 

There  are  no  large  pieces  to  handle;  therefore^  no  special  lift- 
ing facilities  are  required^  but  such  shipyards  as  can  conveniently 
handle  large  sections  could  complete  large  sections  on  the  ground^ 
if  desired. 

The  difficulty  of  doing  overhead  "  welding  has  been  strongly 
emphasized  by  welding  experts^  and  this  has  been  kept  in  view  and 
obviated^  or  at  any  rate  so  far  as  the    strength    welds  are  concerned. 

A  slight  departure  from  riveted  practice  is  to  make  some  of 
the  side  and  bottom  shell  plates  much  wider  than  would  ordinarily 
be  the  case  for  a  ship  of  this  size. 

As  it  happened  in  this  design^  a  length  of  plate  of  22  ft.  fitted 
in  admirably  with  the  arrangements^  and  has  the  maximum  area 
which  would  be  supplied  from  the  mills  in  Great  Britain  for  a  plate 
of  the  thickness^  yiz.  :  1^  inch  without  "  extra." 

Three  longitudinals  are  fitted  on  these  plates^  and  are  butted 
at  the  shell  butts  in  order  that  the  longitudinals  can  be  welded  to 
the  plates  on  the  ground.  There  is  no  reason  why^  if  desired^  two 
plates  or  large  sections  might  not  be  welded  together  on  the  ground^ 
and  the  longitudinals  fitted  in  44-ft.  lengths^  but  this^  as  pre- 
viously mentioned^  depends  on  the  builders'  facilities. 

*  Courtesy  of  J.  W.  Isherwood. 

253 


^4 


APPENDIX 


The  clips  of  the  transverse  members  being  in  short  pieces 
are  also  welded  on  to  the  plates  on  the  ground. 

The  seams  and  butts  of  the  bottom  plating  are  butted  "  and 
fitted  with  outside  straps. 

The  seams  of  the  side  plating  are  arranged  clinker  fashion  in 
order  to  obviate  overhead  strength  welding. 

The  vertical  stiff eners  to  the  floors  are  fitted  in  the  shop  and 
in  cases  like  this^  viz.:  of  stiff eners  and  not  strength  connections 
and  where  only  an  odd  hole  or  two  could  be  saved  by  weldings  it  is 
suggested  that  riveting  be  adopted.  The  same  remarks  apply  to 
the  horizontal     clips  "  on  side  transverse  and  so  on. 

The  longitudinals  and  transverse  "  attachment  angles  are  welded 
to  the  plates  in  the  shop  similarly  to  the  bottom  plates.  The 
gunwale  bar  in  addition  to  the  longitudinal  and  transverse  attach- 
ments is  welded  to  the  sheerstrake  before  erection. 

The  tank-top  margin  angle  is  also  welded  to  the  shell  plate 
abreast  it  before  erection. 

The  side  transverse  members  and  transverse  deep  beams  are 
assembled  and  welded  on  the  ground  in  such  sections  as  are  con- 
venient to  the  builders^  that  is^  the  beam  part  can  be  secured  to  the 
side  transverse  frame  either  before  or  after  erection  as  desired. 

The  tank-top  plates  and  deck  plates  have  both  the  longitudinals 
and  transverse  attachments  welded  to  the  plate  in  the  shop.  It 
will^  of  course^  be  appreciated  that  where  the  longitudinal  forms 
the  seam  strap  it  can  only  be  welded  to  the  edge  of  one  of  the  plates. 
The  completion  of  the  connection  is^  however^  a  very  simple  matter^ 
being  only  an  ordinary  downward  butt  weld. 

The  process  of  erection  and  the  welding  to  be  done  in  the  ship 
might  be  briefly  described^  bearing  in  mind  that  no  special  facilities 
of  any  kind  are  required  for  handling  the  material  beyond  what 
would  be  in  use  in  an  ordinary  shipyard  which  would  ordinarily 
build  a  riveted  vessel  of  the  same  dimensions. 

The  keel  plates  are  laid  as  usual^  they  have  already  welded  to 
them  the  angle  bars  to  take  the  centre  girder  and  the  outside  straps 


APPENDIX 


255 


in  way  of  the  seams  and  also  at  one  end  of  each  plate  to  complete 
the  butt  with  the  next  plate. 

The  plates  for  the  next  strake  are  brought  into  position^  they 
have  in  addition  to  the  longitudinals  and  transverse  framing  clips^ 
edge  strips  welded  along  one  edge  to  form  the  seams  for  the  adjoin- 
ing strake  and  edge  strips  at  one  end  of  each  plate  to  form  the 
butt  of  the  next  plate. 

This  procedure  is  adopted  until  all  the  bottom  plates  are  laid 
in  position^  the  seams  and  butt  strips  forming  convenient  rests  for 
consecutive  plates  and  the  service  holes  for  holding  the  plates  in 
approximate  position. 

The  floors  are  then  dropped  into  position  (it  might  here  be 
remarked  that  the  floors  are  widely  spaced ;  in  this  particular  example 
they  are  5  ft.  6  in.  apart)  and  secured  to  the  longitudinal  by  bolts 
through  the  outstanding  flanges  of  the  vertical  angles  on  the  floors. 

When  a  suflicient  number  of  tank-top  plates^  with  the  longi- 
tudinals and  transverse  clips  already  welded  on^  are  laid  in  position 
so  as  to  adjust  and  fair  the  bottom  components^  the  welding  opera- 
tions on  the  ship  can  be  commenced. 

As  soon  as  the  margin  plate  of  tank  top  is  adjusted  to  its 
proper  position^  the  transverse  frames^  which  are  11  ft.  apart,  are 
erected  and  shoved  in  place. 

The  sooner  the  sheerstrake,  which  has  already  welded  to  it  the 
longitudinal  frame  and  gunwale  bar,  can  be  brought  into  position, 
the  more  readily  can  the  side  plating  with  its  framing  work  be 
erected  and  faired. 

Welding  can,  of  course,  be  commenced  on  the  side  as  soon  as 
a  suflficient  section  is  faired  and  secured. 

The  deck  transverse  beams,  if  not  already  lifted  into  position 
with  the  side  frame,  are  then  placed  in  position  and  secured.  The 
deck  plates,  with  the  longitudinals  already  welded  on,  are  dropped 
into  position  and  the  deck  faired,  when  all  the  welding  now  to  be 
done  in  the  ship  can  be  proceeded  with.  I  wish  to  draw  attention 
to  the  very  small  amount  of  welding  to  be  done  on  the  ship. 


256 


APPENDIX 


DOUBLE  BOTTOM 

Full  welds:  Butt  seams  bottom  plating. 

Butt  straps  of  bottom  plating  and  butts  of  longitudinals. 
Connection  centre  keelson  plate — ^top  and  bottom. 
Seams  of  tank-top  plating. 

Butts  of  tank-top  plates  and  butts  of  longitudinals. 
I  might  here  remark  that  Lloyd's  chief  surveyors  have  intimated 
their  approval  of  the  butting  of  the  tank-top  plating  at  the  centre 
line  in  order  to  obviate  overhead  full  welding. 
Light  welds :  One  edge  of  outside  seam  strap. 

Top  and  bottom  of  floor  plates  to  transverse  clips ;  floors  5  ft. 
6  in.  apart^  giving  ample  room  for  working. 
If  the  service  holes  in  the  seams  and  butts  are  filled  with  plugs 
and  welded  and  the  small  connections  at  the  intersection  of  the 
longitudinals  with  the  floor  plates  are  welded^  then  all  riveting  in 
the  double  bottom  on  the  ship  is  obviated. 

It  is  assumed  that  the  service  holes  for  the  work  done  in  the 
ship  were  filled  up  before  the  material  was  brought  to  the  ship 
and  before  erection. 

SIDE  PLATING  AND   INTERNAL  WORK 

Full  welds:  Outside  edges  of  shell  overlaps. 

Butts  of  shell  plates  and  longitudinals. 

Connection  of  transverse  plates  to  shell  clips. 

Connection  of  transverse  to  inner-bottom  plating. 
Light  welds:  Inside  edges  of  shell  overlaps. 

DECK  AND  INTERNAL  WORK 

Full  welds:  Seams  of  deck  plating. 

Butts  of  deck  plating  and  longitudinals. 
Heel  of  gunwale  bar. 
Connection  of  beam  to  transverse. 
Light  welds:  Connection  of  transverse  beam  plates  to  clips  already 
on  deck. 
Pillar  and  detail  work. 
The  same  remarks  apply  in  regard  to  the  filling  of  service  holes. 


APPENDIX 


259 


MID5HIP  5E.CTIOIN 

QiM ^^,?,lo^^;^-LE.N<■.THCsP    30  ^ -O  ReCAPTHK--"  4Z-- 9  DCPTM  23-4 
l5HeewOOO  SysTEM  (P^^CrsT^ 

 fooP  DCCK  STgl~c.ce  .30  Ot-CK  50. 


I: 


TXAwsvEe^E.  TMeoofeH  Beams  in  >/cluh2'.  4o' 


<C€.  BARS.  5..  48  B  A. 


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260  APPENDIX 

p  4 


APPENDIX 


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plate:  N?25B 


264 


APPENDIX 


INSTRUCTION! 

CH/IRl 

r  WITH 

STANDARD  6YMB0L5 

SHIP  1  

TECPNOIOOYI 

NAME.  OF 
ARTICLE. 

'1 

GALVAWIZt 


FINI5H 


UNnNi6H 


5IZE  OF 
MATERIAL 


ORyj&H 


TACK 


LAVtR*  ~ 


KIND  or 
WELD 


|ReiMrOR(fD[--|rLU6H 


TYPE  OF 
WELD 


SCRAPE  CHISEL 


PREPARATION 
FOR  WELD 


STRENGTH 

~  LAYCRS 


COMPOSITE 


CONCAVE 


HEAT 


FLUX 


1  STRAP  1  1  BUTT  | — |   LAP  |  

TYPE  OF 
JOI/MT 

— jriLLET[— 

PLUG  —  TEE. 

O        □  A 

V       o  ^ 

1  S'NjiLE:  1 — |ooaoLL  1 — |5TRA\CiHT| — 

OESiaN  OF 
WELD 

 1   SlWGLE  1  

1     BCVEU  1 

OOUDLE. 
OEVEU 

>         X  X 

FLAT  — HflRIZONT/ll  — 

F  H 

POSITION  OF 

WELD 

—  VERTICUL —  OVERHEAD 
V  o 

z 

o 
o 
« 

o 
z 

I 

tt 


STEEL 

"3:— 


ELECTRODES 

M  ATCRIAU 

3RASS 

SPECIAL 

1 

ELECTRODE 

6IZE.S 

COVERED 


1  SOURCE,  or 

MAnts  or 

FUNDAMENTAL 

DIFFtRSNCt 

1  POWtR 

VJElUOtRS 

TECHNICAL 

EDUCATION 

1 N  U5E. 

5SARY 
XCAUTIONS 


APPENDIX 


265 


TYPE  OF  JOINT 


STRAP  weld  is  one  in  which  the  seam  of  two 
adjoining  plates  or  surfaces  is  reinforced  by 
any  form  or  shape  to  add  strength  and  stability 
to  the  joint  or  plate.     In  this  form  of  weld 
the  seam  can  only  be  welded  from  the  side  of  the 
work  opposite  the  reinforcement,  and  the  rein- 
forcement of  whatever  shape  must  be  welded  from 
the  side  of  the  work  to  which  the  reinforcement 
is  applied. 


BUTT 


□ 


BUTT  weld  is  one  in  which  two  plates  or 
surfaces  are  brought  together  edge  to  edge  and 
welded  along  the  seam  thus  fomjed.    The  two 
plates  when  so  welded,  form  a  perfectly  flat 
plane  in  themselves  excluding  the  possible 
projective  caused  by  other  individual  objects 
as  frames,  straps,  stiff eners,  etc.,  or 
the  building  up  of  the  weld  proper. 


LAP 


LAP  weld  is  one  in  which  the  edges  of 
two  plates  are  set  one  above  the  other  and  the 
welding  material  so  applied  as  to  bind  the  edge 
of  one  plate  to  the  face  of  the  other  plate. 
In  this  form  of  weld  the  seam  or  lap  forms 
a  raised  surface  along  its  entire  extent. 


266  APPENDIX 

TYPE  OF  JOINT 


FILLET.  ^''••u^ 


PILIET  weld  is  one  in  which  some 
fixture  or  member  is  welded  to  the  face  of  a 
plate,  by  welding  along  the  vertical  edge  of 
the  fixture  or  member  (see  "welds"  s'nown  and 
marked  "A"  on  illustration  at  left).  The 
welding  material  is  applied  in  the  corner  thus 
formed  and  finished  at  an  angle  of  forty-five 
degrees  to  the  plate. 


PLUG 


PLUG  weld  is  one  used  to  connect  tne 
metals  by  welding  through  a  hole  in  either 
one  plate  (Pig.  "A")  or  both  plates  (Fig.  "B"). 
Also  used  for  filling  through  a  bolt  hole 
as  at  (Pig.  "C"),  or  for  added  strength  when 
fastening  fixtures  to  the  face  of  a  plate  by 
drilling  a  countersunk  hole  through  the 
material  (Pig.  "D")  and  applying  the  welding 
material  through  this  hole,  as  at  (Pig.  "D"), 
thereby  fastening  the  fixture  to  the  plate 
at;  this  point. 


TEE 


TEE  weld  is  one  where  one  plate  is 
welded  vertically  to  another  as  in  the  case  of 
the  edge  of  a  transverse  bulkhead  (Pig.  "A") 
being  welded  against  the  shellplating  or  deck. 
This  is  a  weld  which  in  all  cases  requires 
EXCEPTIOKAL  care  and  can  only  be  used  where 
it  is  possible  to  work  from  both  sides  of 
the  vertical  plate.    Also  used  for  welding  a 
rod  in  a  vertical  position  to  a  flat  surface, 
as  the  rung  of  a  ladder  (Pig.  "C"],  or  a 
plate  welded  vertically  to  a  pipe  stanchion 
(Pig.  "B"),  as  in  the  case  of  water  closet 
stalls. 


APPENDIX 


267 


DESIGN  OF  WLLD 


SINGLE  V  ANt"IMKK««»5Jif 


SINGLE  "V"  is  a  terra  applied  to  the  "edge 
finish"  of  a  plate  when  this  edge  is  bevelled  from 
BOTH  sides  to  an  angle,  the  degrees  of  which  are 
left  to  the  designer.    To  he  used  when  the  "V" 
side  of  the  plate  is  to  he  a  maximum  "strength" 
■weld,  with  the  plate  setting  vertically  to  the 
face  of  an  adjoining  member,  and  only  when  the- 
electrode  can  be  applied  from  both  sides  of  the 
work. 


j<- SPACE 


SPACE 
/^NY  THICKNESS  TQ 


DOUBLE  "V"  is  a  term  applied  to  the  "edge 
finish"  of  two  adjoining  plates  v/hen  the  adjoin- 
ing edges  of  both  plates  are  bevelled  from  BOTH 
sides  to  an  angle,  the  degrees  of  which  are  left 
to  the  designer.     To  be  used  v/hen  the  two  plates 
are  to  be  "butted"  together  along  these  two  sides 
for  a  maximum  "strength"  weld.    Only  to  be  used 
when  welding  can  be  performed  from  both  sides  of 
the  plate. 


STRAIGHT  ""^^ 

[sPACe  SHOULD  j! 

j<EauAL  */z  or  |<> 

J  (^PLATtTHICKNtSS  Kl 


SPACE  SHOULD  MUAL 
yi  or  PLATE  THICKNESS 
PLUS  /ft" 


STRAIGHT  is  a  term  applied  to  the  "edge 
^pf^g^g^  finish"  of  a  plate,  when  this  edge  is  left  in 
^)lgt^iima»iM  crude  or  sheared  state.  To  be  used 

'  'only  where  maximum  strength  is  HOT  essen- 

tial, or  unless  used  in  connection  v/ith  strap, 
stiff ener  or  frame,  or  where  it  is  impos- 
sible to  otherwise  finish  the  edge.     Also  to 
be  used  for  a  "strength"  weld,  when  edges  of 
two  plates  set  vertically  to  each  other,— 
as  the  edge  of  a  box. 


SIN6LL  StVCL 

ys"  f  OR    THICK  Plt.  on  ttsO 


3 


1  ^  \|j_^_J^O»^S..rPEHEK.   


SINGLE  BEVEL  is  a  terra  applied  to  the 
edge  finish  of  a  plate,  when  this,  edge  is 
bevelled  from  OKE  side  only  to  an  angle,  the 
degrees  of  which  are  left  to  the  designer.  To 
be  used  for  "strength"  welding,  when  the  elec- 
trode can  be  applied  from  ONE  side  of  the  plate 
only,  or  where  it  is  impossible  to  finish  the 
adjoining  welding  surface. 


OOUBIC  BCVCL 

l-SPACE 


SPACE  .. 
ANY  THICKNESS  '/^ 


w 


-THIS  MEMBER  MAY  BE 
OMITTED  IF  MOT  A  FRAMe. 
&TKAP  OK  STtrPKNER. 


DOUBLE  BEVEL  is  a  terra  applied  to,  the 
edge  finish  of  two  adjoining  plates,  when  the 
adjoining  edges  of  both  plates  are  hevelled  from 
0KB  side  only  to  an  angle,  the  degrees  of  which 
are  left  to  the  designer.    To  be  used  where 
maximum  strength  is  required,  and  where  elec- 
trode can  be  applied  f rom  OKB  side  of  the 
work  only. 


268 


APPENDIX 


PLAT  position  is  determined  when  the  v/elding  material  is  applied  to  a 
surface  on  the  same  plane  as  the  deck,  allowing  the  electrode  to  he  held  in  an 
upright  or  vertical  position.    The  welding  surface  may  be  entirely  on  a  plane 
with  the  deck,  or  one  side  may  he  vertical  to  the  deck  and  welded  to  an  adjoining 
Toemher  that  is  on  a  plane  with  the  deck, 

HORIZONTAL  position  is  determined  when  the  welding  material  is"  applied 
to  a  seam  or  opening,  the  plane  of  which  is  vertical  to  the  deck  and  the  line  of 
weld  is  parallel  with  the  deck,  allowing  the  electrode  to  he  held  in  an  inboard 
or  outboard  position. 

VERTICAL  position  is  determined  when  the  welding  material  is  applied 
to  a  surface  or  seam,  whose  line  extends  in  a  direction  from  one  deck  to  the 
deck  above,  regardless  of  whether  the  adjoining  members  are  on  a  single  plane  or 
at  an  angle  to  each  other.    In  this  position  of  weld,  the  electrode  would  also  bei 
held  in  a  partially  horizontal  position  to  the  work* 

OVERHEUD  position  is  determined  when  the  welding  material  is  applied 
from  the  under  side  of  any  member  whose  plane  is  parallel  to  the  deck  and 
necessitates  the  electrode  being  held  in  a  downright  or  inverted  position. 


APPENDIX 


269 


KmO  Of •  WELD 


TACK 


A  TACK  weld  is  applying  the  welding  mat- 
erial in  small  sections  to  hold  two  edges  to- 
gether, and  should  always  "be  specified  hy  giving 
the  SPACE  from  center  to  center  of  weld  and  the 
LENGTH  of  the  weld  itself.    No  particular 
■^Design  of  weld"  is  necessary  of  consideration* 
A  TACK  is  also  used  for  temporarily  hold- 
ing material  in  place  that  is  to  be  solid- 
ly welded,  until  the  proper  alignment  and 
losition  is  obtained,  and  in  this  case,  neither 
the  LENGTH,  SPACE,  or  DESIGN  OP  WELD  are  to  be 
specified. 


CAULKIM6 


A  CAULKING  weld  is  one  in-  which  the  density 
of  the  crystaline  metal^  used  to  close  up  the 
seam  or  opening,  is  such,  that  no  possible 
leaicage  is  visible  under  a  water,  oil  or  air 
pressure  of  25  lbs.  per  square  inch.    The  ulti- 
mate strength  of  a  caulking  weld  is  not  of  mat-: 
erial  importance,-  neither  is  the  "Design  of 
weld"  of  this  kind  necessary  of  consideration. 
^    The  operator  must  be  the  judge  in  the  number 
of  layers  needed  for  a  tight  weld,  although  tho 
designer  should  specify  a  minimum  amount  of 
layers* 


STRENGTH 


A  STRENGTH  weld  is  one  in  v/hich  the  sec- 
tional area  of  the  welding  material  must  be  so 
considered  that  its  tensile  strength  and  el- 
ongation per  square  inch  must  be  equal  at  least 
60%  of  the  ultimate  strength  per  square  inch  of 
the  surrounding  material.     (To  be  determined 
and  specified  by  the  designer).    The  welding 
material  can  be  applied  in  any  number  of  layers 
beyond  a  minimum  specified  by  the  designer. 

The  density  of  the  crystaline  metals  is 
NOT  of  vital  importance.    In  this  form  of  weld, 
the  "Design  of  weld"*must  be  specified  by 
the  designer  and  followed  by  the  operator. 


COMPOSITE 


270  APPENDIX 


•TYPE- or  WELD- 


REIKPORCED  is  a  term  applied  to  a  weld  when  the  top  layer  of  the  welding 
material  is  built  up  above  the  plane  of  the  surrounding  material  as  at  Fig.  "A"  or 
Pig.  "B"  above,  or  when  used  for  a  corner  as  in  Pig.  "C".    The  top  of  final  layer 
should  project  above  a  plane  of  45  degrees  to  the  adjoining  material.  This  45  degrees 
line  is  shown  "dotted"  in  Pig."C"  above.  This  type  is  chiefly  used  in  a  "Strength"  or 
"Composite"  kind  of  weld  for  the  purpose  of  obtaining  the  maximum  strength  efficiency, 
and  should  be  specified  by  the  designer,  together  with  a  minimum  number  of  layers  of 
welding  material. 


PLUSH  is  a  term  applied  to  a  weld  when  the  top  layer  is  finished  perfectly 
flat  or  on  the  same  plane  as  on  the  adjoining  material  as  shown  at  Pigs.  "D"  and  "E"  above 
or  at  an  angle  of  45  degrees  when  used  to  connect  two  surfaces  at  an  angle  to  each  other 
as  at  Pig.-"P"  above.    This  type  of  weld  is  to  be  used  where  a  maximum 'tensile  strength 
is  not  all  important  and  must  be  specified  by  the  designer,  together  with  a  minimum 
number  of  layers  of  welding  material. 


CONCAVE  is  a  term  aijplied  to  a  weld  when  the  top  layer  finishes  below  the 
plane  of  the  surrounding  material  as  at  Pig.  "G"  above,  or  beneath  a  plane  of  45  degrees 
at  an  angular  connection  as  at  Figs.  "H"  and  "J"  above. 

To  be  used  as  a  weld  of  no  further  importance  than  filling  in  a  seam  or 
opening,  or  for  strictly  caulking  purposes,  when  it  is  found  that  a  minimum  amount  of 
welding  material  will  suffice  to  sustain  a  specified  pound  square  inch  pressure  without 
leakage.     In  this  ^'Type  of  weld"  it  will  not  be  necessary  for  the  designer  ordinarily 
to  specify  the  number  of  layers  of  material  owing  to  the  Mck  of  structural  importance. 


APPENDIX 


271 


.COMBINATIONS  -  OF  -  SYMBOLS. 


S STRAP  WELB  REINFORdE^ 
COMPOSITE  OF  3  LAVeRS, 
VERTICAL,  STRAIGHT. 

3    2  I 


PLATE 


STRAP 


PLATE 


This  sketch  and  symbol  shows  a  strap 
holding  two  plates  together,  setting  vertical- 
ly, with  the  welding  material  applied  in  not 
less  than  three  layers  at  each  edge  of  the 
strap,  as  well  as  between  the  plates  with  a 
reinforced  composite  finish,  so  as  to  malce 
tho  welded  seams  absolutely  water,  air  or 
oiltight,  and  to  attain  the  maximum  tensile 
strength.    The  edges  of  the  strap  and  the 
plates  are  left  in  a  natural  or  sheared 
finish.    This  type  of  welding  is  used  for 
most  particular  kind  of  work  where jaaximum 
strains  are  to  be  sustained* 


/—\    STRAP  V/ELP,  FLUSH, 
(83H0F)    STRENGTH    OF  3  LAYERS, 
HORIZONTAL,  FLAT  ANP 
OVER  HEAP,  POUBLE     BtV  EU. 


PLATE 


HORIZONTAU  WELt? 


STRAP 


This  illustrations  shows  a  strap  holding 
two  plates  together  horizontally,  welded  as  a 
strength  member  with  a  minimum  of  three 
layers  and  a  flush  finish.     Inasmuch  as  the 
strap  necessitates  welding  of  the  plates 
from  one  side  only,  both  edges  of  the  plates 
are  bevelled  to  an  angle,  the  degrees  of 
which  are  left  to  the  discretion  of  the  de- 
signer.   The  edges  of  the  strap  are  left  in 
a  natural  or  sheared  state,  and  the  maximum 
strength  is  attained  by  the  mode  of  applying 
the  welding  material,  and  through  the  sec- 
tional area  per  square  inch  exceeding  the 
sectional  area  of  the  surrounding  material. 


1^3  F 


STRAf^  TACK.,  OVERHEAD, 
8"  CENTER    TO  CENTER, 
4"  LONG,  BUJT,  REINFORCEP, 
composite:  op   3  LAYERS, 
FLAT,  STRAI^>*T 


This  symbol  represents  two  plates  butted 
together  and  welded  flat,  v/ith  a  composite 
weld  of  not  less  than  three  layers,  and  a 
reinforced  finish.    A  strap  is  attached  by 
means  of  overhead  tacking,  the  tacks  being 
four  inches  long  and  spaced  eight  inches 
from  center  to  center.     In  this  case,  the 
v/elding  of  the  plates  is  of  maximum  strength 
and  water,  air  or  oiltight,  but  the  tacking 
is  either  for  the  purpose  of  holding  the 
strap  in  place  until  it  may  be  continuously 
welded,  or  because  strength  is  not  essential. 
All  the  edges  are  left  in  their  natural 
or  sheared  state. 


272 


APPENDIX 


COMBINATIONS     OF   SYMBOLS  (coNT.Nueo) 


ft  F 

.  X 


BUTT  WEILP,  concave:, 

caulking  of  z  layetrs, 
flat:  straight. 


FLAT  wen 


The  symbol  shown  represents  a  Butt 
Weld  between  two  plates  with  the  welding 
material  finished  concaved  and  applied 
in  a  minimum  of  two  layers  to  take  the 
place  of  caulking.    The  edges  of  the 
plates  are  left  in  a  natural  shear  cut 
finish.    This  Symbol  will  be  quite  fre- 
quently used  for  deck  plating  or  any 
other  place  where  strength  is  not  essea- 
tial,  but  where  the  material  must 
vrater,  air  or  oiltight. 


6TRAIQHT 


83  V 
X 


&UTT  WEUO,  REINFORCED, 
STRENGTH  or  3  LAYERS, 
VERTICAL,    DOUBLE  VEE, 


-OOUBUE.  VEE 


PLATE. 


plate: 


VERTICAU  V4M 


This  Symbol  is  used  where  the 
edges  of  two  plates  are  vertically  butted 
together  and  welded  as  a  strength  member** 
The  edges  of  the  adjoining  plates  are 
finished  v/ith  a  "Double  Vee"  and  the  min- 
imum of  three  layers  <of  welding  material 
applied  from  each  side,  finished  with  a 
convex  surface,  thereby  making  the  sec- 
tional area  per  square  inch  of  the  weld, 
greater  than  that  of  the  plates.  This 
will  be  a  conventional  Symbol  for  shell 
plating  or  any  other  members  requiring 
a  max'imum  tensile  strength,  where  the 
welding  can  be  done  from  both  sides  of 
the  work. 


—      BVJTT   V/ELD,  FLUSH, 
93  F     COMPOSITE.  Of   3  LAYERS 
FLAT,    DOUBLE.    BE  VEIL. 


This  Symbol  shows  two  plates  butted 
together  in  a  flat  position  where  the 
•welding  can  only  be  applied  from  the  top 
surface.     It  shows  a  weld  required  for 
plating  v/here  both  strength  and  water- 
tightness  are  to  be  considered.    The 'weld- 
ing material  is  applied  in  a  minimum  of 
three  layers  and  finished  flush  with  the 
level  of  the  plates.    Both  edges  of  the. 
adjoining  plates  are  bevelled  to-  an  angle, 
.the  degrees  of  which  are  left  to  the  dis- 
cretion and  judgment  of  the  designer, 
and  should  only  be  used  when  it  i3  im- 
possible to  weid  from  both  sides  of  the 
work* 


APPENDIX 


273 


.COMBINATIONS  •  OP 'SYMOOLS •  (coMTiNocr). 


LAP  WCLP, 
CAULKING 
OVE.RMEAP 
^TRAIGtti: 


CONCAVE, 
OF    L  LAYERS, 
ANC?  FLAT, 


Flat 


The  sketch  shows  the  edges  of  two 
plates  lapping  each  other  with  the  welding 
material  applied  in  not  less  than  two 
layers  at  each  edge,  with  a  concaved 
caulking  finish,  so  applied  as  to  make 
the  welded  seams  absolutely  water,  air, 
or  oiltight.    The  edges  of  the  plates 
themselves  are  left  in  a  natural  or  sheared 
finish.    Conditions  of  this  kind  will  often 
occur  around  bulkhead  door  frames  where 
maximum  strength  is  not  absolutely 
essential. 


LAP    WELP,  REINFORCE!^ 
STRENGTH    OF  3  LAYERS 
AND    TAC^mG,  I5"CE.NTER 
TO   CENTER.^    6"  L6N6, 
VERTICAL,  5TRA1CiHT 


The  illustration  herein  shown,  is 
somewhat  exaggerated  as  regards  the  bend- 
ing of  the  plates,  but  it  is  only  shown 
this  way  to  fully  illustrate  the  tack  and 
continuous  weld.    It  shows  the  edges  of 
the  plates  lapped  with  one  edge  welded 
v/ith  a  continuous  weld  of  a  minimum  of 
three  layers  with  a  reinforced  finish,, 
thereby  giving  a  maximum  tensile  strength 
to  the  weld,  and  the  other  edge  of  the 
plate,  tack  welded.    The  tacks  are  six  inches 
long  with  a  space  of  12  inches  betv/een  the 
welds  or  18  inches  from  center  to  center 
of  welds.    In  both  cases,  the  edges  of 
plates  are  left  in  a  natural  or  sheared 
state. 


PLUta     ANP    LAP  WELP, 
STRENGTH    OP     3  LAYERS, 
[FLUSH,    FLAT,  OVERHEAP^ 
HORIZONTAL. 


The  sketch  shows  a  condition 
oxa^erated,  which  is  apt  to  occur  in, 
side  plating  where  the  plates  were  held 
in  position  with  bolts  for  the  purpose  of 
alignment  before  being  v;olded.  The 
edges  are  to  be  welded  with  a  minimum  of 
three  layers  of  welding  material  for  a 
strength  weld  and  finished  flush^  and 
after  the  bolts  are  removed,  the  holes 
thus  left  are  to  be  filled  in  with  weld- 
ing material  in  a  manner  prescribed  for 
strength  welding.    The  edges  of  the 
plates  are  to  be  left  in  a  natural  or 
sheared  state,  which  is  customary  in 
most  cases  of  lapped  welding. 


I8 


274 


APPENDIX 


COMBINATIONS  •  OF  •  SYMBOLS*  . 


PLUG  ANP   FILLET  WCLP, 
REIhlFORCEP,  STR£N<5TM  OF 
^^^3  LAYERS,  FLAT,  ^INQLC 
PEveU^  ANP  STRAIGHT 


The  adjoining  sketch  shows  a  pad  eye 
attached  to  a  plate  by  means  of  a  fillet 
weld  along  the  edge  of  the  fixture,  and 
further  strengthened  by  plug  welds  in  two 
countersunk  holes  drilled  in  the  fixture. 
The  welding  material  is  applied  in  a  flat 
position  for  a  strength  weld  with  a  min- 
imum of  three  layers  and  a  reinforced 
finish.    The  edges  of  the  holes  are  bev- 
elled to  an  angle,  which  is  left  to  the 
judgment  of  the  designer,  but  the  edges 
of  the  fixture  are  left  in  their  natural 
state.    This  method  is  used  in  fastening 
fixtures,  clips  or  accessories  that 
w6uld  be  subjected  to  an  excessive  strain 
or  vibration. 


FILLeT     VJELP,  REINFORCEP, 
COMPOSITE    OF    3  LAYERS, 
flat;   VERTICAL  ANP 
OVER  HEAP:,  STRAIGHT 


SE,CTION 
THRO  ArA 


FJLLET  WELP, 
5TREN6TH   OF  3 
FL.AT,  5TRAIQHT, 


LAYER6, 


This  illustration  shows  a  fixture 
attached  to  a  plate  by  means  of  a  composite 
weld  of  not  less  than  three  layers  with  a 
reinforced  finish.    The  fixture  being 
placed  vertically,  necessitates  a  com- 
bination of  flat,  vertical  and  overhead 
welding  in  the  course  of  its  erection. 
Although  a  fixture  of  this  kind  would 
never  be  required  to  be  watertight,  the 
coBiposite  symbol  is  simply  as  a  possi- 
bility of  a  combination. 


This  symbol  represents  a  fixture 
attached  to  a  plate  by  a  strength  fillet 
weld  of  not  less  than  three  layers, 
finished  flush.    The  edges  of  the  fixture 
are  left  in  their  natural  state,  and  the 
welding  material  applied  in  the  corner 
formed  by  the  vertical  edge  of  the 
fixture  in  contact  with  the  face  of  the 
plate. 


APPENDIX 


£75 


,CONDINATI0N5  •  OF  •  5  YMDOL^- (coNtmutD^ 


TEE     V/EUP,  FLUSH, 
6TRENQTH    OF   3  LAYER% 
FLAT,     SINGLE  VEE. 


The  adjoining  sketch  illustrates  the 
edge  of  a  plate  welded  to  the  face  of  another 
plate,  as  in  the  case  of  the  bottom  of  a  trans- 
verse "bulkhead  being  welded  against  the  deck: 
plating.    To  obtain  a  maximum  tensile  strength 
at  the  joint,  the  edge  of  the  plate  is  cut  to  a 
"Single  Vee"  and  welded  on  both  sides  with  a 
strength  weld  of  not  less  than  three  layers,  and 
finished  flush.    This  would  be  Q  convenient  way 
of  fastening  the  intercostals  to  the  keelsons. 
In  this  particular  case,  the  welding  is  done 
in  ^  flat  position. 


TEE  WELD,  REINFORCEP, 
STRENGTH  OF  3  LAYERS, 

jvERTicAL,  amcjLg  vee. 


This  symbol  shows  another  case  of  Tee 
weld  with  the  seam  setting  in  a  vertical 
position,  and  the  welding  material  applied  from 
both  sides  of  the  work.    The  edge  of  the  plate 
is  finished  with  a  "Single  Vee"  and  a  minimum 
of  three  layers  of  welding  material  is  applied 
from  each  side,  finished  with  a  convex  surface, 
t?iereby  making  the  sectional  area,  per  square 
inch  of  the  weld,  greater  than  that  of  the  plate, 
allowing  for  a  maximum  tensile  strength  in  the 
weld. 


^^^^^   STRAP  AND  TEE  VIELP, 

_aZ_L_\    PLy^T     RClNfORCEP  TACK  illustration  herein  shown,  represents 

IZ*' CENTER  TO  CENTC*^    '       example"  of  the  possible  combination  of 
C"  LONQ     SINGLE   BEVEL*      symbols.    An  angle  iron  is  tack  welded  to  the 
OVER  HEAP     STREN6TH   OF  P^^^®  form  of  a  strap  or  stiffener. 


LAVE  R       ,  FLUSH, 


though  in  actual  practice,  this  might  never  occur» 
The  tacks  are  spaced  twelve  inches  from  center 
to  center,  and  are  six  inches  long,  and  applied 
in  a  flat  position,  with  a  reinforced  finish. 
As  the  strap  prevents  welding  the  plate. from 
both  sides,  the  edge  of. the  plate  is  bevelled, 
and  the  welding  material  applied  for  strength 
in  not  less  than  three  layers  in  an  overhead 
position  and  finished  flush.    Note  that  in 
specifying  tack  welds,  it  is  essential  to  give 
the  space  from  center  to  center  of  weld,  and 
length  of  wled  by  use  of  figures  representing 
inches  placed  either  side  of  the  circumscribing 
Sjyrobol  of  the-  combinatipn. 


APPENDIX  VI 


{Lloyd's  Register  of  Shipping.^ 
Application  of  Electric  Arc  Welding  to  Ship  Construction 
introductory  remarks 

Although  electric  welding  in  various  forms  has  been  employed 
for  many  years  for  ship  repair  work^  yet^  in  practice^  owing  to 
many  factors^  its  use  has  been  practically  confined  to  those  parts 
of  the  structure  which  are  not  likely  to  be  exposed  to  important 
structural  stresses. 

It  is  only  in  recent  times^  commencing  from  the  early  days  of 
the  war^  that  appreciable  progress  has  been  made  in  the  developments 
of  electric  welding  which  would  appear  to  justify  the  extension  of 
such  methods  to  replace  the  usual  riveted  connections  of  heavy 
structural  work. 

The  aim  has  been  to  secure  reliability  and  regularity  of  operation 
in  the  welding  process^  and  to  assist  the  workmen  by  improving  the 
means  of  control  over  the  work.  Just  as  in  the  case  of  application 
of  steel  to  shipbuildings  it  was  necessary  to  devise  means  for  the 
production  of  the  material  in  large  quantities  and  of  constant  quality^ 
so  also  is  it  necessary  that  the  welding  electrodes  should  be  manufac- 
tured with  the  greatest  possible  degree  of  uniformity. 

Reliability  of  operation  is  also  facilitated  by  adjusting  the  density 
of  the  electric  current  to  the  size  of  electrode  used^  and^  further^  the 
size  of  the  electrode  should  reasonably  vary  directly  with  the  thick- 
ness of  material  to  be  connected. 

Research  was  necessary  to  discover  means  for  minimizing  the 
burning  of  the  deposited  material  in  the  direction  of  preventing 
oxidation.  In  the  early  days  of  weldings  the  molten  electrode  was 
exposed  to  air  throughout  the  whole  time  of  deposition  and  con- 
sequently oxidation  was  more  or  less  certain  to  occur.  With  coated 
276 


APPENDIX 


277 


metal  electrodes^  burning  is  reduced  to  a  minimum  by  the  use  of  a 
slag  which  envelops  the  molten  steel  and  floats  on  its  surface  after 
contact  is  obtained  with  the  material  to  be  connected.  Even  in  this 
system^  skilled  workmanship  is  essential^  as  the  production  of  a  long 
arc  obviously  increases  the  chances  of  burning. 

The  composition  of  the  material  of  the  electrode  in  relation  to 
the  nature  of  the  steel  to  be  connected  is  obviously  a  matter  of 
importance.  What  the  composition  is  to  be  can  only  be  gauged  by 
experiment  and  by  wide  experience^  and  it  is  in  devising  the  physical 
tests  for  work  of  this  nature  that  the  greatest  difficulties  arise. 

It  is  commonly  accepted  that  the  tests  imposed  on  manufactured 
material  do  not  in  any  way  represent  the  strains  which  may  be 
experienced  in  practice.  Such  tests  are  rather  based  on  simple  means 
for  determining  the  average  reliability  of  the  material.  Thus  also 
is  this  case  no  one  particular  test  is  likely  to  determine  whether  the 
welding  process  under  trial  is  sufficient  for  the  work  it  is  likely  to 
have  to  do. 

It  is  therefore  necessary  to  approach  the  problem  rather  on  the 
basis  of  circumstantial  evidence  and  to  decide  from  a  number  of 
diff*erent  types  of  experiments  whether^  on  the  whole^  the  perform- 
ance is  satisfactory. 

The  more  particular  problem  in  shipbuilding  is  the  connection 
of  mild  steel  containing  a  percentage  of  carbon  of  about  .15.  This 
material  in  the  form  of  plates  and  section  bars  has  considerable 
work  done  to  it  during  the  process  of  manufacture^  with  the  con- 
sequence that  it  possesses  a  fine  structure  and  a  ductility  which  is 
uniform  in  any  direction.  The  finished  material  may  be  said  to  be 
practically  free  from  fibrous  structure. 

With  electric  weldings  molten  metal  is  attached  to  the  mild 
steel  and  from  the  extent  of  the  cooling  surface  the  deposited  material 
is  rapidly  lower  in  temperature^  with  the  consequence  that  the  weld 
tends  to  become  deficient  in  ductility. 

The  problem  therefore  is  to  select  the  material  of  the  electrode 
so  that  the  general  elastic  properties  of  the  structure  are  not 
unduly  depreciated. 


278 


APPENDIX 


The  investigations  were  undertaken  to  determine  the  possibilities 
of  the  application  of  electric  welding  to  shipbuilding  and  as  it  was 
desired  to  obtain  as  good  a  knowledge  as  possible  of  the  physical 
properties  of  the  combination  of  rolled  and  welded  material^  highly 
skilled  operators  were  employed. 

It  must  therefore  be  realized  that  the  results  of  the  experiments 
which  have  been  made  represent  skilled  practice^  and  that  in  general 
such  performance  can  only  be  equalled  with  good  workmanship  and 
efficient  supervision. 

NATURE  AND  DESCRIPTION  OF  EXPERIMENTS 

The  general  scope  of  the  experiments  included: — 

(a)  Determination  of  modulus  of  elasticity  and  approximate 
elastic  limit. 

(b)  Determination    of     ultimate    strength    and  ultimate 
elongation. 

(c)  Application  of  alternating  stresses  with — 

( 1 )  rotating  specimens^ 

(2)  stationary  test  pieces. 

(d)  Minor  tests^  such  as — 

(1)  cold  bending  of  welds^ 

(2)  impact  tests  of  welded  specimens. 

(e)  Chemical  and  microscopic  analysis. 

Tests  were  carried  out  on  specimens  as  large  as  possible^  par- 
ticularly in  respect  to  the  static  determination  of  elasticity^  ultimate 
strength  and  elongation^  some  of  the  test  specimens  being  designed 
for  a  total  load  of  just  under  300  tons.  The  advantage  of  these 
large  specimens  was  that  the  effect  of  workmanship  was  better 
averaged  and  the  results  were  more  comparable  to  the  actual  work 
likely  to  be  met  with  in  ship  construction. 

With  alternating  stresses  the  specimens  were  relatively  of  small 
size.  For  the  rotating  test  pieces,  circular  rods,  mainly  machined 
from  a  welded  plate,  were  used,  the  diameters  selected  being  1  inch 
and  %  inch.  These  bars,  about  3  feet  in  length,  were  attached  to  a 
lathe  headstock  and  a  pure  bending  moment  in  one  plane  was  applied 


APPENDIX 


279 


by  means  of  two  ball  races  to  which  known  weights  were  attached. 
The  material  of  the  bar  was  thus  exposed  alternately  to  maximum 
tension  and  to  equal  maximum  compression  once  in  each  revolution. 
The  machine  was  run  at  about  1^060  revolutions  per  minute. 

Bars  of  identical  material  were  tried  in  pairs^  one  specimen 
welded  and  the  other  unwelded^  and  the  number  of  revolutions  before 
the  specimens  parted  was  observed  for  various  ranges  of  stresses 
varying  from  ±15  tons  to  ±  6  tons. 

In  the  second  series  of  alternating  stress  experiments^  flat  plates 
were  used  of  three  thicknesses^  viz. — 1/4  inch^  %  inch^  and  14  inch. 
These  specimens  were  tried  in  groups  of  four^  each  group  consisting 
of  one  plain^  one  butt-welded^  one  lap-welded  and  one  lap-riveted 
plate.  The  specimens^  which  were  about  14  inches  long  by  5  inches 
broad^  were  clamped  along  the  short  edges^  so  that  the  distance 
between  the  fixed  lines  was  12  inches.  Each  plate  was  also  clamped^ 
near  the  middle^  to  the  end  of  a  pillar^  which  by  means  of  a  crank 
arm  was  caused  to  oscillate  and  to  bend  the  specimen  equally  up  and 
down  by  adjustable  amounts  (the  maximum  total  movement  in  any  of 
the  experiments  tried  was  5/1 6  inch).  The  machine  was  run  at  vari- 
ous revolutions  (not  exceeding  QO  per  minute)  and  the  number  of 
repetitions  at  which  the  specimen  parted  was  observed. 

Minor  tests  of  various  kinds  were  undertaken^  of  which  the 
principal  ones  had  reference  to  the  suitability  of  the  welded  material 
to  withstand  such  bending  and  shock  stresses  as  might  occur  in 
the  shipbuilding  yards.  The  experiments  on  bending  consisted  of 
doubling  the  welded  plate  over  a  circular  bar  of  diameter  equal 
to  three  times  the  plate  thickness^  and  comparing  the  results  with 
those  of  the  plate  of  the  same  material  but  unwelded. 

In  the  impact  tests^  heavy  weights  were  dropped  from  various 
heights  on  to  the  welded  portion  of  a  plate  5  feet  in  length  and  2 
feet  6  inches  in  breadth^  the  weld  being  across  the  plate  parallel 
to  the  shorter,  edge.  The  deflections  were  noted  and  the  condition  of 
the  weld  was  examined  after  each  blow. 

The  chemical  and  micrographical  examination  followed  the 
ordinary  practice. 


280 


APPENDIX 


SUMMARY  OF  EXPERIMENTAL  RESULTS 

1.  Modulus  of  Elasticity  and  Approximate  Elastic  Limit, 

(a)  In  a  welded  plate  the  extensions  in  the  region  of  the  weld  are 
sensibly  the  same  as  for  more  distant  portions  of  the  unwelded  plate. 

(6)  With  small  welded  specimens  containing  an  appreciable 
proportion  of  welded  material  in  the  cross-sectional  area^  the  rela- 
tion between  extension  and  stress  is  practically  the  same,  up  to  the 
elastic  limit_,  as  for  similar  unwelded  material. 

(c)  The  elastic  limit  (or  the  limiting  stress  beyond  which  exten- 
sion is  not  approximately  directly  proportional  to  stress)  appears  to 
be  slightly  higher  in  welded  than  in  unwelded  material. 

{d)  The  modulus  of  elasticity  of  a  small  test  piece,  entirely  com- 
posed of  material  of  the  weld,  was  about  11,700  tons  per  square 
inch  as  compared  with  about  13,500  tons  for  mild  steel  and  about 
12,500  tons  for  wrought  iron. 

2,  Ultimate  Strength  and  Ultimate  Elongation. 

(a)  The  ultimate  strength  of  welded  material  with  small  speci- 
mens was  over  100  per  cent,  of  the  strength  of  the  unwelded  steel 
plate  for  thicknesses  of  %  inch,  and  averaged  90 -per  cent,  for  plates 
%  and  1  inch  in  thickness. 

(6)  Up  to  the  point  of  fracture,  the  extensions  of  the  welded 
specimens  are  not  sensibly  different  from  those  of  similar  un- 
welded material. 

(c)  At  stresses  greater  than  the  elastic  limit,  the  welded  material 
is  less  ductile  than  mild  steel,  and  the  ultimate  elongation  of  a 
welded  specimen  when  measured  on  a  length  of  8  inches  only 
averages  about  10  per  cent,  as  compared  with  25  to  30  per  cent, 
for  mild  steel. 

S,  Alternating  Stresses. 

(a)  Rotating  Specimens  (round  bar). 

(1)  Unwelded  turned  bars  will  withstand  a  very  large  number 
of  repetitions  of  stress  (exceeding,  say,  5  millions)  when  the  range 


APPENDIX 


281 


of  stress  is  not  greater  than  from  10^  tons  per  square  inch  tension 
to  IOY2  tons  per  square  inch  compression. 

(2)  Welded  bars  similarly  tested  will  fail  at  about  the  same 
number  of  repetitions  when  the  range  of  stress  exceeds  ±  6%  tons 
per  square  inch. 

(6)  Stationary  Test  Pieces  {fiat  plate), 

(1)  Butt-welded  specimens  will  withstand  about  70  per  cent,  of 
the  number  of  repetitions  which  can  be  borne  by  an  unwelded  plate. 

(2)  Lap-welded  plates  can  endure  over  6O  per  cent,  of  the 
number  of  repetitions  necessary  to  fracture  a  lap-riveted  specimen. 

^.  Minor  Tests. 

(a)  Welded  specimens  are  not  capable  of  being  bent  (without 
fracture)  over  the  prescribed  radius  to  more  than  80  degrees  with 
^-inch  plate^  reducing  to  some  20  degrees  where  the  thickness  is  1 
inch.  Unwelded  material  under  the  same  conditions  can  be  bent 
through  180  degrees. 

(b)  Welded  plates  can  withstand  impact  with  a  considerable 
degree  of  success;  a  half-inch  plate  of  dimensions  already  quoted 
sustained  two  successive  blows  of  4  cwt.  dropped  through  12  feet^ 
giving  a  deflection  of  12  inches  on  a  length  of  about  4  feet  6  inches 
without  any  signs  of  fracture  in  the  weld. 

5.  Chemical  and  Microscopic  Analysis. 

(a)  Chemical  Analysis. 

(1)  The  electrode  was  practically  identical  with  mild  steely  but 
there  was  a  greater  percentage  of  silicon. 

(2)  The  material  of  the  weld  after  deposition  was  ascertained  to 
be  practically  pure  iron^  the  various  other  contents  being  carbon  .OS, 
silicon  .02^  phosphorus  .02^  and  manganese  .04  per  cent,  respectively. 

(b)  Microscopic  Examination. 

(1)  The  material  of  the  weld  is  practically  pure  iron. 

(2)  The  local  effect  of  heat  does  not  appear  to  largely  affect 
the  surrounding  material,  the  structure  not  being  much  disturbed 
at  about  I/I6  of  an  inch  from  the  edge  of  the  weld.  The  amount  of 
disturbance  is  still  less  in  thin  plates. 


282  APPENDIX 

(3)  The  weld  bears  little  evidence^  if  any^  of  the  occurrence 
of  oxidation. 

(4)  With  welds  made  as  for  these  experiments^  i.e.,  with  flat 
horizontal  weldings  a  sound  junction  is  obtained  between  the  plate 
and  the  welding  material. 

6.  Strength  of  Welds  (Large  Specimens). 

(a)  Butt  Welds  have  a  tensile  strength  varying  from  90  to  95 
per  cent,  of  the  tensile  strength  of  the  unwelded  plate. 

(b)  Lap  Welds, 

(1)  With  full  fillets  on  both  edges  the  ultimate  strength  in 
tension  varies  from  70  to  80  per  cent,  of  that  of  the  unwelded  material. 

(2)  With  a  full  fillet  on  one  edge  and  a  single  run  of  weld  on 
the  other  edge  the  results  are  very  little  inferior  to  those  where  a 
full  fillet  is  provided  for  both  edges. 

(c)  Riveted  Lap  Joints.  For  plates  of  about  %  inch  in  thick- 
ness^ the  specimens  averaged  about  65  to  70  per  cent,  of  the  strength 
of  the  unperf orated  plate. 

OBSERVATIONS  ON  EXPERIMENTAL  RESULTS 

(1)  Static  Elasticity.  It  will  be  observed  that  the  statical  tests 
made  to  determine  the  elasticity  indicate  that^  in  general^  the  com- 
bination of  welded  and  unwelded  material  behaves  practically  homo- 
geneously up  to  at  least  the  elastic  limit.  Moreover^  the  experiments 
show  that  the  process  of  welding  is  such  that  the  stress  is  distrib- 
uted practically  uniformly  over  the  weld^  and  also  transmitted  uni- 
formly to  the  adjacent  plates. 

The  material  of  the  weld  is  practically  pure  iron^  and  from  the 
tests  made  on  a  specimen  composed  entirely  of  the  deposited  material 
of  a  weld^  it  will  be  seen  that  for  a  given  stress  the  weld  stretches 
slightly  more  than  mild  steel.  This  property  will  enable  any  undue 
occurrence  of  load  being  transferred  in  a  proper  manner  to  adjacent 
portions  of  the  structure. 

When^  however^  the  stress  exceeds  the  elastic  limit  and  is  so  great 
that  the  extension  grows  continuously  without  increase  of  load^  the 
welded  material  fails  sooner  than  mild  steel.    This  disadvantage  is^ 


APPENDIX 


283 


however^  of  little  practical  importance  in  shipbuildings  and  may  be 
regarded  as  negligible  in  the  particular  problem  under  consideration. 

(2)  Dynamic  Elasticity,  In  a  structure^  such  as  a  ship^  which 
is  exposed  to  variations  and  reversal  stresses^  it  is  extremely  important 
to  know  whether  the  material  to  be  used  is  likely  to  break  down 
rapidly  under  such  alternations  and  ranges  of  stress  as  are  likely  to 
be  experienced.  The  modified  Wohler  tests  employed  in  the  experi- 
ments certainly  indicate^  if  considered  solely  by  themselves^  that 
whereas  for  a  given  number  of  alternations  mild  steel  would  withstand 
a  range  of  stress  of^  say^  ±  10^/^  tons^  the  welded  material  might  be 
expected  to  fail  at  about  ±  6V2  tons,  a  figure  which  is  more  nearly 
experienced  in  ordinary  ship  construction. 

It  would  appear  to  be  necessary  to  design  the  welded  joints  in 
such  a  manner  that  the  amount  of  work  likely  to  be  thrown  on  the 
joint  is  as  small  as  possible,  and  to  meet  such  a  condition  a  welded 
joint  requires  to  be  either  lapped  or  strapped. 

It  will  be  noticed  that  the  material  in  the  weld  appears  to  be 
nearly  pure  iron,  and  experiments  of  repetitive  stress  show  that 
wrought-iron  bars  are  likely  to  fail  under  a  range  of  stress  of  per- 
haps ±  7  to  8  tons  as  compared  with  mild  steel  at  ±  10  to  11  tons. 
The  weld  has  to  be  deposited  electrically  and  is  subject  to  variations 
in  workmanship;  it  would  consequently  be  considered  satisfactory  if 
the  material  could  withstand  a  range  of  stress  of,  say,  i  6^  tons. 

Consideration  of  the  dynamic-elasticity  properties  appears  to  show 
that  in  any  case  the  welded  material  can  experience  as  large  a  num- 
ber of  repetitions  of  stress  as  wrougjit  iron  could  do,  and  it  is  always 
recognized  that  although  iron  could  not  approach  the  tests'  for  mild 
steel,  yet  it  was  a  satisfactory  material  for  shipbuilding  purposes. 
Further,  attention  to  design  of  details  will  increase  the  performance 
of  the  welded  joint,  and  in  addition  it  must  not  be  forgotten  that 
5,000,000  repetitions  of  stress  is  perhaps  more  than  equivalent  to  10 
years'  good  sea  service. 

{S)  Physical  Nature  and  Properties.  It  has  been  mentioned  that 
the  welds  experimented  with  are  to  be  regarded  as  having  been 
produced  under  most  favorable  conditions,  and  that  throughout 


284 


APPENDIX 


the  experimental  welds  were  made  with  the  specimens  horizontal  and 
below  the  operator.  In  practice^  welds  will  require  to  be  made  ver- 
tically and  overhead  as  well^  consequently  extreme  care  will  be 
required  in  such  operations. 

The  physical  examinations  indicate  that  the  materials  of  the 
electrode  and  the  system  of  welding  adopted  were  suitable  and  reli- 
able. Moreover^  there  was  little  apparent  oxidation  and  the  material 
in  the  neighborhood  of  the  weld  was  not  affected  to  any  pre- 
judicial extent. 

(^)  Strength  of  Welds  and  Minor  Tests.  Broadly  speakings  the 
tensile  strength  of  butt  welds  was  as  great  as  the  unwelded  material^ 
but  it  is  considered  that  greater  reliability  of  workmanship  is  obtained 
with  joints  which  are  either  lapped  or  strapped. 

It  was  also  found  that  the  lapped  joint  was  practically  as  strong 
as  a  riveted  lapped  joint  and  would  probably  remain  tight  when 
subjected  to  more  trying  conditions  than  are  necessary  to  disturb  a 
riveted  lap  joint. 

In  view  of  the  satisfactory  results  of  the  extensive  and  exhaustive 
trials  which  have  been  carried  out  on  electric  arc  welds^  the  Com- 
mittee have  decided  to  adopts  as  a  tentative  measure^  the  following 
Provisional  Rules  for  classification  in  Lloyd's  Register  Book  of 
vessels  electrically  welded^  subject  to  the  notations  Experimental  " 
and  "  Electrically  welded." 

The  approval  of  the  Society  will  be  given  to  any  system  of  weld- 
ing which  complies  with  these  Regulations  and  consideration  will 
be  given  to  any  alternative  constructional  arrangements  which  may 
be  submitted  for  approval. 


APPENDIX  VII 


tentative  regulations  for  the  application  of  electric  arc 
welding  to  ship  construction  ^ 

(a)  system  of  welding  and  workmanship 

(1)  The  system  of  welding  proposed  to  be  used  must  be 
approved  and  must  comply  with  the  regulations  and  tests  laid  down 
by  the  Committee. 

(2)  The  process  of  manufacture  of  the  electrodes  must  be  such 
as  to  ensure  reliability  and  uniformity  in  the  finished  article. 

(3)  Specimens  of  the  finished  electrodes^  together  with  specifi- 
cations of  the  nature  of  the  electrodes^  must  be  supplied  to  the 
Committee  for  purposes  of  record. 

(4)  The  Committee's  officers  shall  have  access  to  the  works 
where  the  electrodes  are  manufactured^  and  will  investigate^  from 
time  to  time  as  may  be  necessary^  the  process  of  manufacture  to 
ensure  that  the  electrodes  are  identical  with  the  approved  specimens. 

(5)  Alterations  from  the  process  approved  for  the  manufacture 
of  electrodes  shall  not  be  made  without  the  consent  of  the  Committee. 

(6)  The  regulations  for  the  voltage  and  amperage  to  be  used 
with  each  size  of  electrode^  and  for  the  size  of  electrode  to  be  employed 
with  different  thicknesses  of  material  to  be  joined^  are  to  be  approved 
by  the  Committee. 

(7)  The  Committee  must  be  satisfied  that  the  operators  engaged 
are  specially  trained^  and  are  experienced  and  efficient  in  the  use 
of  the  welding  system  proposed  to  be  employed. 

(8)  Efficient  supervisors  of  proved  ability  must  be  provided^ 
and  the  proportion  of  supervisors  to  welders  must  be  submitted 
for  approval. 

*  Issued  by  Lloyd's  Register  of  Shipping. 

285 


286 


APPENDIX 


(b)  details  of  construction 

(9)  The  details  of  construction  of  the  vessel  and  of  the  welds 
are  to  be  submitted  for  approval. 

(10)  Before  weldings  the  surfaces  to  be  joined  must  be  fitted 
close  to  each  other  and  the  methods  to  be  adopted  for  this  purpose 
are  to  be  approved. 

(11)  All  butt  and  edge  connections  are  to  be  lapped  or  strapped. 

(12)  With  lapped  connections  the  breadths  of  overlaps  of  butts 
and  seams  and  the  profiles  of  the  welds  to  be  in  accordance  with  the 
following  table: — 


Thickness 
of  plate. 
Inches. 

Width  of  overlap 
seam  and  butt. 
Inches 

Throat 
thickness 
Inches. 

  21/4 

.28 

.60  

 21/2 

.38 

.80   

  23/4 

.48 

1.00  

 3 

.50 

Intermediate  values  may  be  obtained  by  direct  interpolation^  and 
for  thicknesses  below  .40  the  throat  thickness  is  to  be  about  70  per 
cent,  of  the  thickness  of  the  plate. 

(13)  A  ''full  weld"  extends  from  the  edge  of  a  plate  for  a 
distance  equal  to  the  thickness  of  plate  to  be  attached^  and  the 
minimum  measurement  from  the  inner  edge  of  plate  to  the  surface 
of  weld  is  the  throat  thickness  given  in  the  table  above. 

(14)  A  ''light  closing  weld"  is  a  single  run  of  light  welding 
worked  continuously  along  the  edge  of  the  plate.  Such  a  weld  may, 
however,  be  interrupted  where  it  crosses  the  connection  of  another 
member  of  the  structure. 

(15)  An  "  intermittent  or  tack  weld  "  has  short  lengths  of  weld 
which  are  spaced  three  times  the  length  of  the  weld  from  centre  to 
centre  of  each  short  length  of  weld.  Such  tack  welding  may  vary 
in  amount  of  weld  between  a  "  full  weld  "  and  a  "  light  closing  weld." 

(16)  The  general  character  of  welds  is  to  be  in  accordance  with 
the  following  table: — 


APPENDIX 


287 


(a)  Butts  of  shelly  deck  and  inner-bottom  plating] 

(b)  Butts  of  longitudinal  girders  and  hatch  coam-  | 

ings  J 

(c)  Edges  of  shelly  deck  and  inner-bottom  plating 

(d)  Butts  and  edges  of  bulkhead  plating 

(e)  Frames  to  shelly  reverse  frames  to  frames  and 

floors 

(f)  Beams  to  decks 

(g)  Longitudinal  continuous  angles 

(h)  Side  girders^  bars  to  shelly  intercostal  plates^ 

floors  and  inner  bottom 
(z)  Bulkhead  stiff eners 

F  =  full  weld,  L  =  light  weld,  and  T  =  tack  weld. 


Inside  Outside 
edge.  edge. 


L 

Toe. 


F 

Heel. 


(17)  All  bars  required  to  be  watertight  are  to  have  continuous 
welding  on  both  flanges  with  tack  welding  at  heel  of  bar. 

(18)  The  welded  connections  of  beam^  frame  and  other  brack- 
ets are  to  be  submitted  for  special  consideration. 

(19)  The  Committee  may  require^  when  considered  necessary^ 
additional  attachment  beyond  that  specified  above^  and  the  welding 
of  all  other  parts  is  to  be  to  their  approval. 


APPENDIX 


INDEX 


Abell,  W.  S.,  175,  176 

Air  pressure  for  welding  machines, 

40,  44 
Alleman,  Gellert,  200 
Amer.  Inst.  Mining  Engineers,  126, 

198,  203 
Angle  of  bevel,  109 
Annealing,  2,  3 

of  steel,  11,  12 
Archives  des  Sciences,  213 
Arc,  characteristics,  201 

long,  148,  207 

short  128,  148,  201,  206,  234 
starting  the,  228 
Arc  welders,  131,  134-5,  137-8,  140, 
142 

protection  of,  146 
lessons,  148-159,  224,  227 
Arc  welding,  180 

alternating  current,  116,  208,  211 

apparatus,  power  for,  289 

beads,  148,  229 

boiler  flue,  246 

carbon  arc,  17,  248 

cast  iron,  123,  250 

cost  of,  166 

current,  116,  120 

design  of  weld,  267 

electrode  position,  149,  234 

examples,  100,  103 

flexibility  of  tools,  98 

in  repair  work,  97 

kind  of  weld,  269 

layers,  110,  236 

manufacturing,  101 

method  of  assembly,  121 


Arc  welding,  miscellaneous  jobs,  213 
oil  tanks,  162 

overhead,  157-8,  202,  209,  211,  238, 
253 

padding  153,  156,  231 

position  of  work.  111,  128,  151, 

156-8,  268 
preparation  of,  233 
pressure  work,  240 
railroads,  99,  220 

rate  of  heat,  149,  155-6,  199,  201, 
207,  212,  235 

ship  joints,  163 

spreading,  152 

steel  castings,  248 

steel  plate,  233 

symbols,  137,  264,  271 

theories,  197,  203,  210,  213 

thin  materials,  155,  239 

time  of,  128,  166 

type  of  joint,  265 

type  of  weld,  270 
Assembly  methods,  121 
Autogeneous  welding,  179 
Automatic  arc  welding,  125,  203 

Beads,  arc  welding,  148,  229 
Boiler  flue  welding,  246 
Brazing,  179 

Bureau  of  Standards,  147 
Butt  welding,  14,  180,  182 

Caldwell,  James,  165,  168 
Capacity  of  spot  welding  machines, 
44,  48,  49 

291 


292 


INDEX 


Capacity  of  transformers  for  spot 

welding,  46 
Capp,  J.  A.,  180 
Carbon  arc  welding,  17,  248 
Carbon  content  of  steel,  5,  9,  183, 

198 

Cast  iron,  3,  123,  250 

Caulking  rivets  with  arc,  246 

Chemical  and  metallurgical  en- 
gineering, 181 

Chicago,  Rock  Island  &  Pacific 
Railway,  99,  220 

Comfmercial  Museum,  73 

Comstock,  G.  F.,  198 

Conductivity  of  heat,,  spot  welding, 
194 

Connections  of  testing  instruments, 
67 

Costs  in  repair,  100,  166 
Cox,  H.  J.,  58 

Current,  arc  welding,  116,  120 
in  spot  welding  electrodes,  43 
large  spot  welding  machine,  46 

Design  of  ships,  167,  170-1,  173,  253, 
285 

Design  of  weld,  109,  267 
Diameter  of  spot,  192 
Direct  current,  224 
Duplex   welding   machine,  descrip- 
tion, 44 

East    Coast    Inst.    Engineers  and 

Shipbuilders,  175-6 
Electric  Arc  Cutting  and  Welding 

Co.,  159,  288 
Electrically  welded  ship,  160,  161, 
162. 

design  of,  167 
Electric  blow-pipe  method,  21 
Electric  weldability  of  steel,  10 
Electric  welding,  processes  of,  14 


Electrodes,  arc  welding,  148,  201, 
206,  212 

bare  and  covered,  19,  112,  129,  151, 

152 
coated,  115 

composition  of,  108,  128 
current,  116,  120 
gaseous  flux,  20 
Liquid  flux,  20 
position  of,  149,  234 
practice  with,  227 
size  of,  120 

specifications  of,  108,  221 
Electrodes,    spot    welding,  adjust- 
ment of,  45,  95 
cooling  of,  45 
current  in,  43 

for  spot  welding  machines,  42 

protection  of  tip,  92 

Weed,  on  design  of,  43 
Emergency  Fleet  Corporation  spot 
welding  machines,  42 

designs  of,  170 

requirements  of,  47 

schools,  136-7 
English  coasting  vessel,  176 
English  cross-channel  barge,  165 
Escholz,  O.  H.,  203 
Exhibit  of  welding,  73 
Experimental  spot  welding  machine, 

34 

Franklin  Institute,  Journal  of,  200 
Frequency,  117 

Gaseous  flux  covering,  20 
Geary,  Dorothea  M.,  163 
General  Electric  Co.,  18,  28,  29,  34, 

43,  46,  59,  104,   147,  163-4,  180, 

198 

Genera;tor,  adjustment  of,  226 
operation  of,  224 


INDEX 


293 


Hagenbach  and  Langbein,  213 
Hamilton  and  Oberg,  1,  22,  27,  29, 
30,  3G 

Heat,  rate  for  arc  welding,  149,  155, 
156,  201,  207,  212,  235 

conductivity  for  spot  welding,  194 

theory  of  spot  welding,  180,  185 
Heaton,  T.  T.,  113 
Holslag,  H.  J.,  lessons  of,  148-159 

theories  of,  209 
Howe,  H.  M.,  2,  5-7,  10-12,  185 

effect  of  carbon,  on  weldability  of 
steel,  10 
Hudson,  R.  G.,  211 

Inspection  of  spot  welding,  91 
Institute  of  Mechanical  Engineers, 

London,  113. 
Investigations  suggested,  133 
Iron,  production  of,  2 

welding  of  cast  iron,  123,  250 

wrought,  4 
Isherwood,  J.  W.,  design,  173,  253 

Kjelberg,  114 

Langbein,  Hagenbach  and,  213 
Lincoln  Electric  Co.,  97,  224 
Liquid  flux  covering,  20 
Liston,  John,  163 

Lloyd's  Register  of  Shipping,  rules 
for  welded  ship,  174,  276,  285 
ship's  parts  welded,  161,  218,  256 
spot  welding  tests,  58,  192 
uniformity  tests,  80 

Long  arc,  148,  207 

Materials,  cleanliness  of,  75,  129 
fracturing,  193 
position  of,  151,  156 
preparation  for  arc  welding,  233 
preparation  for  spot  welding,  94 


Materials,  thin  arc  welding,  155,  239 

thin  spot  welding,  24 
McClintock-Marshall,  tests  of  spot 

welding,  49 
Merrill,  W.  L.,  34 
Metallic  arc  welding,  18,  113 
Metallurgical  theories,  arc  welding, 
197 

spot  welding,  181 
Miller,  S.  W.,  185,  188-191,  198 
Morton  Harry  D.,  125-6  203 

Nauticus,  170 

Nitrogen  content  of  steel,  198,  201, 
207 

Occluded  gases,  199,  201 
Oil  barge,  165 

Operation  welding  generator,  224 
Operators,  training  of,  131 
Osborn,  J.  A.,  29,  30 
Overhead  welding,  157,  202,  209  211, 

238,  253 
Oxidation,  148 

Padding,  arc  welding,  153,  156,  231 
Physical  theories,  arc  welding,  203, 

210 
Pig  iron,  3 
Pinch  effect,  213 
Position  of  weld.  111,  268 
Power   for  arc  welding  machines, 

289 

Pressure  welding,  240 
Quasi- Arc,  113 

Reactance  in  spot  welding  machine, 
39,  44 

Regulating  panels  for  spot  welding 
machine,  46 


294 


INDEX 


Reinforced  weld,  lOT 
Resistance  welding,  180 
Riveting  in  shipbuilding,  32,  36 

comparison  of,  72 
Rivets,  caulking  with  arc,  246 

shearing  stress  of,  89 
Rudder,  W.  E.,  198 
Rules,  Lloyd's,  174 

Seam  welding,  17 

Schools,  136,  137,  140 

Ship  construction,  designs  of,  167, 

170,  173,  253 
5-foot  spot  welding,  machine  for, 

56 

pounding  test,  62 
spot  welding  in,  29,  37 
spot  welded  floor,  60 
transverse  plating,  171 

Shipping  Board,  reports  to,  165 

Ships,  electrically  welded,  105,  160, 
161  162,  165 
combination  joint,  163 
welded  motor  boat,  163 
English  coasting  vessel,  176 
English  cross-channel  barge,  165 
first  welded  motorboat,  163 
Lloyd's  rules,  174,  218,  276,  285 
oil  barge,  165 

Short  arc,  128,  148,  201,  206,  234 

Slavianoff'  process,  18,  113 

Slocum,  A.  W.,  210 

Soldering,  179 

Specifications  for  electrodes,  108,  221 
Spot  welding,  14,  15,  182 

application  of  light  spot  welding, 
27 

diameter,  192 
fundamentals  of,  24 
heat  conductivity,  194 
in  ship  construction,  29,  37 


Spot  welding,  inspection  of,  91 
making  single  spot,  47 
of  railroad  cars  29 
pounding  test,  60 
preparation  of  materials,  94 
ship's  floors,  60 
surfaces,  75 

tests  at  New  York  Shipbuilding 

Corporation,  30 
test  results,  63 
theories  of,  180,  185 
theories,  metallurgical,  181 
thin  materials,  24 
uniformity  tests,  62,  80 
Spot    welding    machines,  arrange- 
ments for  tests,  51 
air  pressure  of,  40,  44 
capacity  of  duplex,  44,  48 
capacity  of  small  machines,  49 
capacity  of  trens  formers  for,  46 
current  in  electrodes,  43 
current  in  large  machines,  46 
electrodes  for,  42 
experimental  machines,  34 
5-foot  portable,  description  of,  56 
for    shipbuilding  demonstration, 
56 

high  tension  supplied  for,  57 
making  single  spots,  47 
operating  voltage,  43 
reactance,  39,  44 
regulating  panel  for  transformers 
for,  46 

small  portable,  description  of,  42 

tests,  49,  51 

transformer  design,  42 

transformers  for,  46 

voltage,  drop  of,  58,  87 
Spreading,  arc  welding,  152 
Starting  the  arc,  228 
Steel,  2,  3 


INDEX 


295 


Steel,  annealing  of,  11,  12 

carbon  in,  5,  9,  183  198 

chemical  constituents  of,  5 

crucible,  4 

definition  of,  2 

hardening  of,  11 

joining  of,  89,  223 

manufacture  of,  4 

nitrogen  in,  198,  201,  207 

open  hearth,  4 

plates  and  shapes,  5,  105 

tempering  of,  11 

weldability  of,  8,  10 
Steel  casting,  248 
Strohmenger,  Arthur,  113 
Surface  for  spot  welding,  75 
Symbols  for  arc  welding,  137,  264,  271 

Target  keel,  166 

Tests,  arc  welding,  174-5 

connection  of  instruments,  67 
Lloyd's  spot  welding,  58,  80,  192 
of  spot  welding  machines,  49,  51 
of  welds,  118 
pounding  ships'  floors,  62 
results  of  spot  welding,  63 
ships'  plates,  105 

tabulations,  64,  66-9,  70,  74,  76-9, 

81-6,  88 
tank  welded  122 
uniformity,  spot  welding,  62,  80 
Theories  arc  welding,  197,  203,  210, 

213 

electrical,  205 
heat  180,  185 
metallurgical,  arc,  197 
metallurgical,  spot,  181 
overhead,  202,  209  211 
physical  arc,  203,  210 
spot  welding,  180,  185 
vapor,  213 


Thum,  E.  E.,  181 

Time  of  arc  welding,  128,  166 

Training  of  arc  welders,  131,  134-5, 

137,  140 
Transformer  capacity  for,  46 

design  for  spot  welding  macliines^ 
42 

regulating  panel,  46 
Type  of  weld,  270 

Vapor  theory,  electrical  arc,  213 
Voltage,  across  arc,  288 

drop  for  arc  welding,  205,  211-12 

drop  for  spot  welding,  58,  87 

impressed,  128 

minimum  arc,  206 

open  circuit  arc,  208 

operating,  43 

striking,  113 
Voltex  process,  22 

Wagner,  R.  E.,  18,  104,  122 
Wanamaker,  E.,  99,  116,  220 
Water-pail,  forge  method,  21 
Weed,  J.  M.,  design  of  spot  welding 

machines,  43 
Weld,  design  of,  109,  267,  270 

ductility  of,  123 

position  of.  111,  268 

reinforced,  107 

strength  of,  123 

testing,  118 
Weldability  of  steel,  8 

Howe  on  the,  10 
Welders,  arc,  131,  134 

fitness  of,  142 

lessons,  148-159,  224,  227 

protection  of,  146 

selection  of,  134 

training  of,  131,  134-5,  137-8,  140 


296 


INDEX 


Welding,   alternating    current  arc, 
116,  208,  m 
autogeneous,  179 
automatic  arc,  125,  203 
butt,  14,  180,  182 
cast  iron,  123,  250 
comparison  with  riveting,  72 
definition  of,  178 
in  rows,  63,  194,  215 
layers,  110,  236 
miscellaneous  jobs,  243 


Welding,  of  ships,  160-3,  165 
open  circuit,  208 

overhead,  157-8,  202,  209,  211,  238 
253 

positions  of  work,  arc  welding.  111 
128,  151,  156-8,  268 

proposed  demonstration,  34 

resistance,  180 

ship  plates,  105 
Winne,  H.  A.,  28 
Wrought  iron,  4 


Date  Due 

^  ■  I-  /f 

/Mi 

•s 


